It's not too early to set up your domicile and mail forwarding. Set up all bills on AutoPay and you won't have to worry about getting bills on time.
We didn't do any changes for banking - left them as is - no problems. We used Fidelity, Vanguard, Wells Fargo
RV Clubs - Escapees is the very best for many full-timing issues and puts out a great bi-monthly magazine written by full-timers. It also has a good network of home-owned or Co-op parks.
Camping Clubs - Passport America would be the first one. It very cheap and since you will be flexible in your travels it is easily used. Travel a while to see how it goes before locking yourself into one of the others as they're more expensive. Some are only good for certain areas of the country.
If you're 62+ - definitely get the Senior Pass for national parks, Corp of Engineers, forest service campgrounds. 1/2 off on campsites and free admittance into the parks.
Hope this helps. Best of luck to you in this awesome new lifestyle!!