I obviously don't know the nature of your disability, but you don't have to invest a lot of time, skill, or money doing a build. My build took less than a week. I have no construction skills and did my build using only a drill, saw, and tape measure. And maybe a hammer or wrench, though I don't remember using them. I didn't use any other tools, because that's the entirety of my tool collection. No point in owning tools I don't know how to use... My initial build cost < $4k, no point in buying materials I don't know how to use...
By keeping the build simple, most of the amenities wanted in a van can be purchased already assembled. Bed, kitchenette, toilet, storage, plumbing and electrical power can all be factory built. By keeping the build simple, you don't need someone with specialized expertise. You can hire a local handyman to do the stuff you can't do. I hired someone from Task Rabbit to build a toilet box.
There are a lot of reasons for starting with a simple build. My primary reasons were I wanted something quickly, I didn't want anything that I didn't know how to fix (or easily replace) if needed. I didn't want to spend a lot of money until I gained enough experience to know what I wanted. Down the road, I could add complexity where desired, as my time, knowledge and money allowed.
Here's a video explaining why its advantageous to go simple:
My build includes a lot of amenities (eg. hot water, induction cooktop, microwave, inside shower, diesel heater). Every system is executed in the simplest way that accomplishes the desired task.
Here's a video offering an opinion of what's necessary in a build and how to do it for $1000.
