My husband and I fulltimed for 15 years, till he died on the road. I now part time in a smaller motorhome and I am based in Florida.
You asked about Thousand Trails and KOA. We never did the TT, but know a lot of people who did and still do. There is a buy-in fee, and I believe yearly maintenance fees, but you can camp cheaply after that. If money is tight, I would wait on that till you know you can afford to keep it up. BLM land in the west particularly is cheap or free in most cases, but it is normally primitive, so you still have to think about how to get water, recharge batteries, and dumping your tanks. KOA's are expensive. Some of the campgrounds are old, but if they are still associated with the franchise, you can expect good services from them. A lot of the KOA's are now privately owned and they can be cheaper or expensive. We joined PPA, Passport America which offers 50% off campgrounds in their system. Some are good, some are bad, but we used it enough, we bought a lifetime membership and it paid for itself.
Take a lot of smaller trips and get your plan in order before you leave. As was mentioned, your rig, if it has sat for a long period, will likely give you headaches, so make sure you have planned ($$$) for those. When I sold my 40' diesel pusher it had over 100,000 miles on it, but the fellow who bought it had a diesel mechanic friend who told him to take the one with the most miles because it was well cared for. That is true, especially for a diesel, because keeping anything on the road requires due diligence. Letting it set. . . not so much. If the plan is to let it set. . . buy a trailer instead.
There are a lot of people who work from the road, but it does require an internet connection. Do not rely on campground wifi as it is offered mainly for convenience and not for heavy use by lots of campers. Living full-time in a motorhome is not cheap. Many people have that idea and are sorely disappointed. It offers a lot of adventure and I loved our time on the road. But money was not a problem for us. There are a lot of camping organizations that can offer suggestions: Escapees, FMCA, RVOvernights, to name a few. Check them out for more information.
Dale