I would not recommend Texas as a state to register your truck and RV, you have to return there every other year to have it inspected. Many states do not require inspection of the frame, brakes, and such, they trust the owners to not drive broken down vehicles.
I would suggest looking into Nevada. I hear they do not have excessive high vehicle regerstration, don't think they have smog certificates, and no state income tax. You can also hire a mail box service that can sign for certified mail, and run a small business if you like from that address. You can have your mail forwarded to anyplace in the United States.
Yes it has been done before. Look at the Exscapee's club, they forward mail for many members to all areas of the country! You do need to pick a state, there are advantages to several of them. One being Oregon, where RV registration the first year is kinda expensive, but after that it is fairly low cost, and the sales tax on a replacement vehicle, or anything else is $0 !
Yes you will need to register all your vehicles in one state, and get the drivers license there. Get insurance, and make sure that the policy you get is not void if you spend more than 60 days at a time out of state. Heck you might decide you like to stay in Oregon, less humidity, and very green!
Fred.