By Clayton Houser – Professional van builder (50+ full builds)

Choosing the right base van isn’t about what’s “best” – it’s about the constraints you can’t change later. Clayton breaks down the tradeoffs that matter most, so you pick a platform that fits how you’ll actually travel and live.

This is the third article in Clayton's Van Build series - you can view the series homepage here.

One of the first decisions people want to make when planning a van build is choosing the base vehicle.

They usually ask it like this:
“Which van is best?”

After building a whole lot of vans and talking with hundreds of builders, I don’t think that’s the right way to approach it. There is no single best van. There are only tradeoffs — and those tradeoffs matter differently depending on how you plan to use the van.

If you choose a base van before you’re clear on purpose, you’ll end up designing around limitations instead of intentions.

Purpose Comes First (Again)

Before comparing any specific models, you need to revisit the same questions I mentioned in my last post, which should guide the rest of your build:

• Are you living in the van full-time or using it on weekends?

• Are you staying in campgrounds or traveling off-grid?

• What climates are you traveling through?

• How many people are riding and sleeping?

• How much gear needs to live inside the van?

Your base van choice affects interior space, ride quality, maintenance realities, and how forgiving the build process will be. None of those factors matter on their own — they matter in relation to how you’ll actually use the van.

Many People Choose a Van Too Early

One common mistake I see is people locking in a van before they understand what they’re building toward.

They fall in love with a brand, a look, or a build they saw online. Then they try to force a layout or system into a platform that doesn’t support it easily.

When that happens, everything becomes harder:

• Layouts feel cramped

• Weight becomes an issue

• Systems get complicated

• Maintenance becomes stressful

Choosing a base van should be a result of planning, not the starting point.

Dimensions Matter More Than the Logo

When people focus only on a brand, they often overlook the things that actually affect daily life inside the van.

Two dimensions matter more than almost anything else:

• Roof height

• Body length 

If you’re spending time inside the van — especially living full-time — standing height matters. Bending over every day adds friction you don’t notice at first but feel later.

Body length affects:

• How the interior can be laid out

• How much separation you can have between living zones

• How easy the van is to park and maneuver

Longer vans give you more flexibility inside. Shorter vans are easier to drive and park. Neither is better — they just serve different priorities.

Weight Is a Constraint You Can’t Ignore

Every van has limits. Batteries, water, cabinetry, appliances, and gear all add up faster than people expect.

If weight isn’t considered early, the result can often be:

• Poor handling

• Sagging suspension

• Increased wear on components

• A van that feels unstable on the road

This is one reason I’m cautious about overbuilt furniture and unnecessary materials. Strength matters, but so does restraint.

Your base van sets the ceiling. Everything you add has to live within it.

Serviceability Is Part of the Build

Another factor people underestimate is where and how the van will be serviced.

Some vans are easier to get worked on in small towns. Others rely more on dealerships and specialized diagnostics. That difference matters more once you’re traveling regularly.

If the van is your home, downtime isn’t just inconvenient — it can end a trip.

This doesn’t mean one approach is right or wrong. It means service access should be part of the decision, not an afterthought.

New vs Used: Condition Over Numbers

Mileage gets a lot of attention when people shop for vans, but it’s not the whole story.

What matters just as much:

• Maintenance history

• Signs of hard commercial use

• Rust or corrosion

• Poorly done previous modifications

I’ve seen low-mileage vans with serious issues and higher-mileage vans that were clearly cared for. Condition tells you more than the odometer.

If you’re buying used, plan time to inspect and address issues before starting a build. Rushing this step usually creates problems later.

Common Base-Van Mistakes

A few patterns show up repeatedly:

• Choosing a van based on aesthetics instead of use

• Ignoring interior dimensions until layout design starts

• Underestimating weight early in the build

• Not thinking through service realities

• Locking in a platform before defining purpose

None of these mistakes are fatal, but they all make the build harder than it needs to be.

How to Make the Decision Without Overthinking It

You don’t need to optimize this decision perfectly. You need to make it intentionally.

If you can answer these questions, you’re in a good place:

• Does this van support my intended layout?

• Can it handle the weight of my planned systems?

• Am I comfortable with how it will be serviced?

• Does it fit where and how I plan to travel?

If the answer is yes, it’s probably a workable platform.

What Comes Next

Once the base van is chosen, the build becomes real. The next step is designing the layout — and for me, that always starts with the bed.

That decision anchors everything else.

Vanlife Outfitters Note: How the Base Van Platform Affects Your Build

Clayton’s guidance focuses on purpose first. Once that purpose is clear, the base van becomes a structural constraint that shapes layout options, system capacity, and long-term usability.

This section provides high-level context on the three most common platforms used by DIY van builders. It is not a recommendation or ranking — it is meant to help you understand how platform differences influence build decisions.

Mercedes-Benz Sprinter

The Sprinter is often chosen when a build priority is either a desire for four-wheel drive or maximum interior runway, with high-roof options and longer body lengths that support more expansive layouts and more configuration flexibility.

Sprinter is also a common pick because it’s a Mercedes – some builders want more premium feel, comfort, and tech, and they are willing to pay more for it. As you may expect, Sprinter vans are significantly more expensive than Ford or Dodge vans.

On the other hand, Sprinters usually have diesel engines, which come with both pros and cons – and they can be harder to service on the road in the U.S. because the authorized network is much smaller. Ford and Dodge have thousands of dealerships across the U.S., while Mercedes-Benz Vans only has hundreds. 

A practical way to frame the Sprinter choice is: I want maximum standing room and a longer layout runway, I like the premium Mercedes experience, and I’m comfortable planning around a platform that can be more demanding to own long term. 

Here is a link to Sprinter details, and here is a link to find MB Van dealers.  

Key implications

• Strong high-roof and longer-length options for larger layout

• Often perceived as more premium inside (comfort/tech/overall feel), but typically costs more than rivals

• Diesel is common in Sprinter configurations (plan for diesel-focused maintenance and operating considerations)

• Fewer branded service points vs Ford/Ram can make “service on the road” require more planning

Ford Transit

The Transit is often chosen by builders who want available AWD, a large OEM and aftermarket support ecosystem, and broad parts and service access for long-term travel.

From a build standpoint, the Transit is not the “square” option. Its interior surfaces curve in multiple areas, which can make wall finishing and cabinetry fit-up more work than boxier platforms like the ProMaster.

A practical way to frame the Transit choice is: I want AWD capability and widespread service support, without stepping into the complexity and ownership profile that some builders associate with Sprinters (not a universal rule, but a common decision pattern.)

Here is a link to Transit details, and here is a link to find Ford Pro dealers. 

Key implications

• Available Intelligent AWD for traction-focused builds

• Strong parts/service network for regular or remote travel

• More interior curvature means more templating and fit work than “square” vans

Ram ProMaster

The ProMaster is often chosen when the build priority is usable interior space and “boxy” interior. Compared with the Sprinter and Transit, it has squarer interior walls and more usable width, which can make layout planning and cabinetry more straightforward for many DIY builders. In addition, it is the only one of the big three van models that is wide enough for a full-length bed running “east-west” without adding flares. 

It’s also a front-wheel-drive platform, and that drivetrain layout is commonly linked to the ProMaster’s lower load floor (easier step-in and loading) compared with the other two. 

And it is usually the cheapest of the three vans. 

A practical way to frame the ProMaster choice is: I want the most build-friendly interior geometry (wide, square walls, low step-in), and I’m comfortable giving up AWD capability in exchange for a lower price and the packaging benefits of a FWD platform.

Here is a link to ProMaster details, and here is a link to find Ram dealers. 

Key implications

• Generally viewed as the widest and most “square” interior of the big three (often simpler for cabinetry and certain layouts).

• Front-wheel drive supports a lower load floor (daily entry and loading convenience).

• Large dealer footprint in the U.S. (roughly ~2.4K Ram locations, depending on dataset and timing), which can make service access easier than smaller networks. 

Platform Choice in Context

No platform is universally “better.” Each introduces constraints that shape design decisions, system sizing, and long-term adaptability. The right choice depends on how the van is intended to be used – now and in the future. 

Understanding these differences early helps ensure that later build decisions align with the purpose defined at the start.

Frequently Asked Questions About Choosing a Base Van

How do interior dimensions compare between Sprinter, Transit, and ProMaster vans?

Interior dimensions vary widely by configuration and roof height, but here are typical 2025 figures:

• Mercedes-Benz Sprinter (High Roof): Interior standing height ~79.1 inches; max floor width ~70 inches; cargo volume up to ~533 cubic feet on extended wheelbases. 

• Ford Transit (High Roof): Interior standing height ~81.5 inches on some high-roof/long configurations; interior width around ~77.0 inches. 

• Ram ProMaster (High Roof): Interior cargo width up to ~75.6 inches and max interior width up to ~75.6 inches. 

These dimensions affect how you can lay out beds, appliances, and storage inside the van.

Which van offers the most interior width for camper conversions?

In general:

• Ford Transit interior width can reach about 77.0 inches, providing slightly more width than other platforms. 

• Ram ProMaster offers up to about 75.6 inches of interior width. 

• Mercedes Sprinter interior width tends to be narrower, typically around 70–70.4 inches at floor level. 

Wider interiors can make layout planning — especially bed orientation and side-to-side storage — more flexible.

Do roof heights differ significantly between cargo vans?

Yes, and roof height significantly influences stand-up space:

• Ford Transit high-roof models can provide an interior height of about 81.5 inches, which is among the tallest in the class. And we know some shorter vanlifers who can even stand up tall in the Transit’s mid-roof models. 

• Mercedes-Benz Sprinter high-roof interior height is typically around 79.1 inches. 

• Ram ProMaster also has high-roof options, with cargo height often around 76 inches, though exact figures vary by model. They even have a new Super High Roof option you may want to consider. 

Remember to take your floor plans into account as you plan for the interior height of your build.

How do payload capacities compare among Sprinter, Transit, and ProMaster?

Payload capacity (the amount of weight a van can carry safely) varies by trim and configuration, but manufacturers report maximum figures such as:

• Ram ProMaster: up to over 4,800 pounds maximum payload on some models. 

• Ford Transit: payloads can range widely; some Transits are rated around 3,500 pounds or more depending on options. 

• Mercedes Sprinter: specific payloads vary across trims, with heavier-duty versions designed to carry larger loads (often higher than light-duty competitors). 

Higher payload can give more margin for batteries, water, gear, and furniture without overloading.

Does wheelbase length make a noticeable difference in build space?

Yes. Longer wheelbase vans offer more interior length for beds, cabinets, and systems:

• Mercedes Sprinters most often have wheelbases of 144” and 170”. 

• Ford Transits are typically 130” and 148”. 

• Ram ProMasters are usually 136” and 159”. 

Although greater interior length improves layout flexibility, it does so with trade-offs like ease of parking and maneuverability.

Are there any other dimensional differences that affect camper van builds?

Beyond width and height, differences include:

• Cargo length: Longer vans like extended Transits and Sprinters provide more bed and storage space.

• Load floor height: Vans like the ProMaster often have lower load floors which can make entering/exiting and loading gear easier. 

• Turning radius and overall exterior dimensions: These affect daily drivability, though they are less directly tied to interior layout.