those Japanese import vans with 4x4 system and some with diesel will fit the bill under 15k. but you probably don't want that. parts would be almost impossible to get on those right hand drive machines.
also, are these considered all wheel drive instead of 4wd? I've never looked into it before.
https://pittsburgh.craigslist.org/ctd/d/chevy-express-vanx4/6356161012.html
edit:
https://www.caranddriver.com/reviews/chevy-express-awd-short-take-road-test
Like this one a lot. If it is there in a day or two may fly out and pull the trigger.
Thanks - kylakemike