Need help weighing the pros and cons of what kind of camper van to buy?

So I plan on moving down to Nashville and living in a van in the very near future. I'm on the fence between 2. The first option is a 1988 Ford e350 diesel dually ambulance that has been fully converted. Running water, inverter, heat, ac. Pretty much everything in an rv besides a toilet. My second option is getting a cargo van and converting it or just getting one of those conversion Van's. I'm just not sure what my best bet is.

I bet the ambulance has worse fuel economy but is more sturdily built. For your purpose it sounds better to me.