Some tips: i which I knew before doing the same:
- If there's a floor, check under for rust
- Take the van for a ride in a rough road, verify that there no weird noises like doors rattling
- Gas is cheaper overall (initial cost and maintenance)
- Try to get a cargo van, is easier to build out, stealthier and safer, plus no windows no leaks to fix, i got the passenger and is a pain in the a** to DIY
- If you get one with a high top, verify for leaks, also make sure that if you get one with a high top the rear doors are still factory (not extended). This is especially true since most conversion companies don't set the right latch configuration to prevent the doors from rattling, is pretty annoying going down the road hearing that awful noise. Also, the factory parts will fit, i.e. weather stripping and latches
Now about conversion:
- I like the way ford build vehicles, that being said I find the Econoline to be a tough one to convert because of the way the body is manufactured. Chevys are 1000 times more square, and easier to insulate since there's only one sheet of metal between the inside and the outside, this point alone makes a huge difference.
- Any of these vehicles are reliable, and you can expect about 250k miles if you dont take care of it, even more, if you do. There's an interesting page the million-mile van, check it out.
- Barn doors will give you more space for stuff than sliding doors
- And again... please don't get a passenger van, windows are a PITA. Is easier to add an aftermarket window than keeping good care of all the windows in a passenger van.