What ever fits your needs better, go with that. If you want to be able to sleep in it more comfortably go with the camper. A short bus can fit a **** ton of gear in it though once you remove the seats. Just know it's going to shift a lot while driving if not secured.
I have a short bus and love it. It was a handicap bus, removed the lift and all the wheel chair securing things. Put in a laminate floor. I found some charter bus seats and put two in the front.
I Keep a cot, 12 volt tiny fridge, little buddy heater, extension cord, 30 amp to 110 convertwr, camp stove, and a 5 gallon bucket with toilet seat lid so I can register it as an rv. The bucket is for ultra mega emergencies only and ideally will never be used also checks an item off the list. I bought a tool chest with a butcher block top for storage and a surface for whatever is needed. I have e track along the walls of the bus for strapping things in.
I'll attach the check list from the iowa DOT of things you need if you are doing a conversion/want to register as an rv.
If registered as an rv, or in an rv, passengers are legally allowed to drink while in motion as long as they are in the "living quarters" if that affects your decison at all
