You should have no problems doing what you describe and it shouldn't be too expensive. If your budget is $75,000 for a used gas MH, you should be able to get a heck of a nice unit with only a few miles on it.
Class As like to be driven. If you plan to move every two months or so, that would be fine. Be sure to run the generator at the same time when you move to keep that in shape. Ideally, you should go through at least one or two tanks of fuel per year to keep that fresh. Get your rig inspected before purchasing and change out the fluids on schedule. You'll be fine.
Most folks who own class A motorhomes hardly ever use them. Many RV dealers and staff have told me that's the number one reason they deteriorate and fall apart. From neglect, not overuse. If you live in it full-time and drive it every two months, you'll be ahead of 90% of the RV crowd.
You haven't told us why you prefer camping over a condo, but I agree with you for my own reasons.
