Many points to consider.
Diesel or Gaz. Diesel have air ride and are smoother, Diesel normally do better MPG, Diesel is more complicated and more expensive to repair, Diesel are quiet as engine is in the back.
Long or short. Short are easier to park, easier to find camping spot, do better MPG.
Rubber roof or aluminun/fiberglass, alu and fiber will last forever.
Floor plan, this is your preference.
19 or 22 inch tires. 22 are more expensive but ride better.
Once you decide, check the tires, they can cost up to $4000. I would not buy a MH with old cracked tires. Brakes, wear, leak, craked disk: the rear cost me $1500.00 and this is a very good price. Leaking radiator, check if you see any seeping from it, mine cost $3000.oo. Test it on the road, check for check engine light, ABS light, turbo in good working order. ect. Check for leaks evidence as smell, discolored lines on wall or cealing, tiny black spots on the bottom or top of the walls and ceilling.
Good luck.