The other members who said they cannot answer because there are so many variables are right. That is part of what makes this an ADVENTURE. You try to prepare, but you still have to take that leap and know that things can be fixed as you go and plans changed on the run. Being flexible is really the most important thing about this lifestyle. As far as maintenance, there are mobile repair people who will come to your site and fix things. For example, after struggling with replacing the seals in my toilet over the last few days, and not being able to reinsert one part that ought to go in, I ended up walking down to chat with the camp hosts in this Corps of Engineering campground. They were able to give me the name and phone number of a mobile repair guy who was certified at RV repair. They said he was reasonable in his charges, but most such people do charge a fee for coming out to you.
I had tried Camping World and another RV dealer in this area and both said they could not fit me in for at least two weeks--a ridiculous situation when you have a barely working toilet!