I’m too new to offer a suggestion on which Van is best to convert, but just wanted to drop in and welcome you to the forums. A lot of nice people here, and more than a few with experience they are happy to pass along.
So again, welcome!
Greetings & Welcome!
A van can be pretty cramped for 2 people. I would strongly consider a Class C motorhome.
If you’re stealth parking on city streets for free, a camper van can have a slight advantage, although I had very little problems parking a small motorhome or bus on city streets. I think the dividing line is whether it will fit in a standard parking space or not. All of mine did.