Any groups or memberships worth joining or avoiding?

Passport America

Escapees RV Club

These are good for finding reasonable camping.

Many communities have city and county parks.

If you're 62+ get the Federal Senior Pass which will give you free entrance into the national parks, national forests, Corp of Engineers, Nat'l Wildlife Refuges and will also give you 1/2 off on camping.

We used all of the above during our 16 years of full-timing. Those, along with boondocking on national forest and BLM lands in the West.

Good luck!