My Promaster Van Build: Rear Entry, Hidden Bath/Shower, and a Few Other Unusual Details

(click images for larger view)

I’m documenting the build of our 2017 Promaster 2500 159″ wheelbase van into a self-contained camper to share my experiences and my approach to its design and configuration with the hope that others might find aspects of it informative.

Here’s the various pages if you want to skip to one directly:

Opening page & Page 1: Intro, Index of pages and History, Van Selection, Floor Plan and  Configuration Design

Page 2&3: Tour

Page 4: Our experiences so far and links to some trip write-ups

Page 5: Windows

Page 6: Insulation and Ventilation

Page 7: Solar Panel

Page 8: Cabinets, Paneling & Plumbing Mock-up

Page 9: Electrical System

Page 10: Refrigerator, Furnace and Propane System

Page 11: Plumbing

Page 12: “Composting” Toilet and a Spreadsheet of Build Costs

History, Van Selection, Purchase and Floor Plan/Configuration Design

My build is a bit different than most van conversions, as it is a rear-entry floor plan with a center aisle and with twin beds/sofas/dinette in the front. This has certain advantages over using the large side sliding door for access, at least for how we use it, which includes a lot off cool weather trips and for use as a work van. It also has a hidden bathtub/shower.

This is actually my second van build, as I converted this used 1968 Dodge A100 van back in 1975. I cut in two sliding aluminum windows, bought some 1/4″ plywood and a sabre saw and paneled the inside walls, and built a rear platform bed. My then-girlfriend made the curtains. We moved to the San Diego Area with it in 1976, and it got lots of use in the deserts and mountains of California. I was hooked.

But then marriage and three kids intervened.

After the two oldest ones were out of the house, the urge to travel more freely again and camp in secluded places made itself felt. In 2002, I bought this ’77 Dodge Chinook for $1200, spruced up the interior some, and we racked up some 40,000 miles on trips all over the West and Baja (full story here). It finally just wore out, although we still were using it for shorter trips until 2017. I had mentally started toying with a replacement after the Mercedes Sprinter first appeared in the US some ten or so years ago.

We boondock on National Forest or BLM land or remote primitive campgrounds or even urban parking lots whenever possible, avoiding busy campgrounds except when necessary. Our experiences with it informed the decisions on the plans for a new van.

The most significant one was the Chinook’s rear entry door and its key floor plan features, such as twin beds in the front that double as couches and dinette, with a removable center-post table. But I also made some significant changes too, as will be described. Our third kid used to sleep in that little fold-down  nook up there, where the bedding is. We called him “bookshelf boy”.

The Chinook had no house or cab air conditioning, and its furnace and hot water heater had both died and I never bothered to fix or replace them. So it was a fairly primitive camper, but that suited us fine.

In 2017 I was ready to buy a new van; the question was which one. I’d been thinking about this since late 2013 when the Ram Promaster and Ford Transit were announced, and I wrote on their various pros and cons here. Already then I favored the Promaster for a few key reasons. Most of all, its FWD allows for a lower cargo area floor, which also means that overall height is lower even with a high roof. And additionally, the Promaster’s body is 4″ wider than the Sprinter and Transit. This simply makes the Promaster a better box, in terms of its proportions, height and space utilization.

Another downside of the Transit is that the extra-tall roof is needed to get stand-up interior height. So equipped, the Transit ends up almost a foot taller than the Promaster, and the Sprinter is almost that tall. The lower floor height of the FWD Promaster allows easier entry, and gives it a lower center of gravity. It also makes it easier to get under possible obstacles, such as tree branches in remote areas. The Promaster is also cheaper than the Sprinter. And I’ve been put off by many stories about expensive service and repair costs on the diesel Sprinter.

I also found that the Promaster’s 159″ EB wheelbase body (and cargo area) length was ideal for my plans. It’s a bit longer (and wider) than the Transit’s EB version and the Sprinter’s RB version, but significantly more compact then their longest versions.

If I was intending to tow a heavy trailer, I’d possibly consider something other the FWD Promaster, although it is rated to tow up to 7,000 lbs (if the van is not loaded to capacity, otherwise 5,000 lbs.) But for our purposes the gas 3.6 L V6 and 6 speed automatic appeared to be perfectly adequate. It has compiled a generally positive track record (of course there are issues to be found on the forums, as with all vehicles), and it’s worked very well for us so far, including several overlanding trips to very remote areas of Eastern Oregon or Saline Valley, CA, (above) on very rough roads normally used only by 4×4 vehicles, much rougher than this section shown here. I’ve only had to back down once, so far.

Update 11/23: after six and half years and some 55,000 miles, the Promaster has been flawless. Not one trip to a dealer or any shop. It’s only required oil changes and a new set of tires (at 44k miles).


As it turns out, the Promaster and the Chinook have the exact same 12′ floor length behind the cab for living space. The Chinook has a wider body, but that turned out not to be an issue.

In May of 2017 I bought a new 2017 Promaster 2500 159″ van from Dave Smith Motors in Kellogg, Idaho. I went that far to buy it because their price was the best I could find. I paid $30,495, or 26% off its MSRP of $38,110. That’s the complete drive-away price with registration (no sales tax in Oregon), for a van with some options like trailer tow package, fog lights, cruise control, and U Connect 5.0 along with a few other minor items (full story here).

Once I had the van at home, I started fleshing out the floor plan. This was the initial plan, which is actually quite close to the final one. At that point I was contemplating a flip-up passenger side bed, as I wanted to be able to use the van to haul tools, appliances and other cargo for maintenance on my rental properties. I ended up doing that a bit differently, an easily removable bed, but with the same end result.

Because of other commitments, I didn’t get started on the van build until almost a year later, but I used the van as my work truck in the meantime. And I used blue tape to flesh out the details of the floor plan.

During this time, I researched to find good information as how to actually build this van. There are many blogs and forums and videos, but not many of them were along the general lines of what I wanted to do, meaning a practical, fairly well equipped van but not a showcase or too complicated or expensive. Pragmatic, in other words. But by far the most helpful one was, which is based on the author’s (Gary) detailed design and build of a 138″ Promaster van.

Gary is a former Boeing engineer, and his very objective and rational approach resonated with me, and it gave me the confidence to tackle a project that I was not experienced with and was a bit intimidating. Gary responded to several questions, and I’m most appreciative of what he’s done and continues to do.

I also spent some time at, and found many useful threads. There are many build threads there, as well as covering the wide range of Promaster issues, tips and insights.

There are many websites and forums and probably hundreds of Youtube videos on van builds, and I surfed some of them, but one can spend an infinite amount of time there, and that ultimately gets in the way of actual building. It can be a challenge sifting through the many competing approaches, theories on insulation, electric systems, etc..

I had a pretty good general idea of what I wanted, meaning a build focused on our travels in the West in generally remote areas and therefor as self sufficient as possible. Fortunately Gary’s van build had many of the same or similar objectives, so that was very helpful, although my build is also somewhat different than his too.

I prioritized functional simplicity, with a nod to the ambiance as well as some creature comforts. Budget obviously plays into the consideration, and although I was not really financially constrained, I didn’t want to spend more than necessary. The total cost of components and materials has been around $7,000, which seems to roughly be the sweet spot between the very low end basic conversions and the high end ones.


Continue on Page 2 (and 3) for The Tour

Return to page 1 for the index of pages

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