Xtal, you have a compelling argument for a DIY trailer, does remove the vehicle issues because now when the vehicle becomes a problem child you can replace with a newer one.
BUT, Wheel chair modified vans might present some challenges, all of the modifications will most likely reduce the cargo capacity of the van.
You would have to carefully control how heavy your DIY trailer gets so you do not exceed the vans leftover cargo rating.
I was going to have a trailer builder that custom builds horse trailers with living space make a frame for me and title it.
Then I was going to build the box on top of that.
Before I was able to give the go ahead, I found a old rotted TT in the length I wanted and bought that for $700 instead, gutted the trailer and made it the way I wanted.
This gave me good windows, good bath tub with surround, good furnace, good A/C, good stove with oven and much more. Windows, doors, furnace, A/C, Stove are insanely expensive to buy new.
Hindsight, I should have removed all the good stuff, then cut the bolts and removed the rotted box then built from scratch and new box. Would have saved me months of work..
I would however, suggest rather than attempting to build from scratch you might want to look up custom horse trailer builders.. Many custom horse trailer builders offer pretty darn nice living quarters and it wouldn't take much work to have them build a all living quarters trailer specifically around your needs..
