Grahamk53,
RVers tend to be a bit anal about the rigs they buy. Virtually every used rig will have some maintenance issues, but rebuilding (within reason) and adding stuff to your rig is all part of the fun. There are really great buys out there where mileage is high. There are really poor buys out there with almost no miles at all. Start looking, listening, shopping, asking for advice and then go out there and see for yourself. As your knowledge increases you'll become more comfortable with the choices you need to make. You have to start somewhere and this forum is a great place to start!