Wife and I were "homeless transient" people (full time travelers) for about 2 years, a few years ago. The suggestion to join Escapees is very valid ( we are still members). We used St. Brendan's Isle for our mail service. They were absolutely great (I have no direct business interest), just a very satisfied customer as is my brother, currently.
The Florida county tag offices are just down the road a few blocks from SBI and they are also very supportive with SBI customers. I even processed new vehicle plates via mail and internet thru them, very helpful.
Hope this helps.
A story - Wife and I visited Oatman, Az, along one of the restored Route 66 sections, then drove south to I-10 at the Az/Cal border. Had a late lunch at the marina bar, looking out a picture window at the boats on the river. We must have looked sort of ragged, as a high spirited lady and her husband came into the bar for lunch. When she asked who we were, I replied we were homeless transient people. She got a concerned look on her face, reached into her purse, and handed me a $20. Wife and I started laughing and handed her money back. We then had an nice impromptu conversation about traveling and such with her and her husband. Then we got into our F550 RV hauler and continued on our way. Morals of the story, be careful how you present yourself, be ready to meet many nice people, and be ready to enjoy a lack of most, if not all, time pressure.