Hello!
I travel frequently and hate staying in hotels. I plan to travel even more this winter and for longer periods of time, trying to get out this winter and tour the country. So I've decided to do some upgrades to make staying in my van much more comfortable on the road.
Hope this new thread is useful to some, and maybe get a few novel ideas for my setup.

I started by wrapping walls, ceiling and floor with EDPM to serve as a vapor barrier and sound dampener. It's the thicker of the two common ones, 60 mil I think. I didn't want to use the stranded EDPM glue indoors, so I glued it with interior carpet glue. It worked very well, it cures flexible and is water resistant. I applied it with a 6" roller, it went on extremely thin so I used multiple coats to build up to a decent layer.
Next I got some 2" thick insulation to go on top of that, it's rated at 7.5 R value, for walls and ceiling. I also installed 1" on the floor.
All of the supports and other framing where I couldn't put that insulation I drilled and filled in with expandable foam, rated around 12 R I think.

Right now I'm hanging strips of plywood I ripped down to 1.75" to pack out the wall studs and supports so I have space between the mylar and future interior wood for a radiant barrier. My goal has been to get at least 1/2" of dead space. Planning on wrapping inside of van with hardwood, ship-lap style.

So EDPM/2" foam/mylar/.5-1.5" gap/.5" hardwood is the order.

My code bot is telling me that could have a R value of 12-14
Radiant barrier is a little difficult to calculate because how well it works depends a lot on whatever heat source is inside.
I think it's going to work well.

I'm still on the fence on other areas, like heat/power/potable water and such so if you guys have any suggestions let me know!
ty!

 

I would focus on keeping the weight down
Those 78's are built quite a bit tougher than any newer ones
Have fun

 

Here's some of my build pics, not much, I can dig up some more if you want some more ideas. On reddit, r/vandwellers and r/vanlife have a lot of great info and resources that you can pull off, and there's also a lot on YouTube. I did 3m thinpsulate in mine no vapor barrier. I recommend a diesel heater, not as bad of an install I thought it would be and I've used it plenty of times. And I recommend trying to build your electrical system instead of a power station, also not too complicated. Also my couch slides out into a bed.

 

Van builds are so versatile, congrats on getting started. Pic is my rig, obviously the shuttle body gives me more space (I can stand inside) but it’s still a van.

#1 item is VENTILATION. Even if you hadn’t just sealed it up tight, that would be important, and now doubly so. Both passive and active. You need separate fresh-in and wet-out, ideally on opposite ends. I suggest “ventshade” accessories on the front windows so you can leave them cracked to let in fresh air, and at least one roof vent with fan, near the rear. Make sure it is fully shrouded so you can run it in the rain. Simply breathing dumps a lot of moisture into the air, so waking up after even a mild night can have all your windows fogged. +100 if you have a dog.

#2 Keep it modular. Avoid building any hard features exactly to fit with some specific product or appliance. Leave wiggle room around anything like a cooktop, chest fridge, power bank, etc.

#3 Use a power bank (jackery, gopower, etc) for your electrical. It’s just so easy, compact, and cost-efficient. Wait for Black Friday. Even if you hard wire your lights and fixtures, use the power bank as the “heart”. Some have an high current Anderson connection for one of their outputs, plug that right into a (fused!!!) distribution block like the excellent ones from Bluesea and run with that. I’ve built two campers and their electrical systems from the ground up, full solar and all electric appliances. It’s easy for me…and I’d still use a powerbank if I were doing a straight up van build.

#4 Seconding the above: Keep it light. Plywood adds up FAST. You don’t want to squat your van, the handling goes to crap.