It depends on what you want to spend. You can go Class C and you will have "Normal" 16" tires, Ford or Chevy Van Chassis which are fairly easy to work on and reliable.
You can go up to a Newer Class A and be in the Bus tire size (19.5 - 22.5") and have a much more durable chassis, but also costs more to maintain.
It then depends on the quality and condition of the "box" on the frame.
I had a 1977 GMC. It was a small Class A Gas and the only real issue was it was old, and mid-70's GM engine was not great, but the body shell was probably the best ever made. It was small, cramped, but cool and had people looking at it all the time.
If I were to buy another older Motorhome, a 1995-1996 Safari (Diesel Pusher) No slides. You can get good ones for very little money and they are very reliable.