I have a 2007 235s on a Chevy chassis. Some things to consider:
1. There is very little exterior storage space. I bought a stowaway2 cargo container for gear and equipment.
2. There is also very little counter space. Actually, there is none. I put a countertop over the stove and bought an induction hot plate for cooking.
3. There is not much room behind the couch. Your memory foam would have to be not more than a couple of inches, if that.
4. The heat duct to the bath room vent runs outside under the chassis on mine. Consequently, it does not provide much heat.
5. The driver's side closet has ample space for shelves in the back while still leaving room for hanging clothes.
6. The front seats are great for storing my GS-Mini while we're camping.
7. Re 98k miles. That's a lot. Perhaps other can speak to it, but I wouldn't pay $30k for something with that many miles. I expect you will face lots of mechanical issue. I paid $34 for mine. It had 4k miles on it.
8. It gets pretty good gas mileage for a motorhome (11-12). It drives like a dream compared to my last Ford chassis motorhome. It's pretty easy to maneuver. You'll have to hog two parking spaces. You still have to watch the rear over hang when turning in close maneuvers, but at 25 ft the overhang is pretty reasonable.
9. Hosting several musicians may be a little optimistic. It gets pretty tight with just the spouse and me moving about. Hope one of the musicians is not a drummer.
Seriously, I can't imagine 4 or 5 people in it for any length of time.
I'm guessing you can pull it off, but you'll be pretty happy when you move back into an apartment - even if it's a small studio. Good Luck!