I've found it! After a few months of searching, I found my new home! It's a 1990 Ford Econoline Cargo Van. It's a 3/4 ton and has a straight 6 engine. Cosmetically, it's hurting pretty bad, so it's going to take a ton of work from myself, my dad and friends to get this guy into the camper that I have in my head.
I'm really excited to start working on it. The plan so far is to add a bed with storage underneath, a small sink/fridge and welded racks on the top and on the front or back.