First RV for full timing: Used or New?

Welcome! And good luck with whatever you choose! Know that you are bound to make some mistakes with choices, everyone does. Let it roll. My first big thing would be the depreciation from the purchase of a new RV. That, if nothing else would lead my to advise a used one, nicely maintained. It would be good if you could find something owned by someone you know. As you said, your first one will probably not be the dream home. Look for any signs of water infiltration, anywhere in the rig. The roof seems to show first, around the A/C, around vents, and corners are usually the first places to leak. If you can get on the roof safely, look closely at all the seams. Cracks are inevitable, but they should show evidence of being sealed. Test all systems, fresh water, waste water (black & grey), 12V, 120V, heat, refrigerator, A/C, and outlets. Look closely inside around doors and windows for cracks, unsealed air leakage, or water entry. Check under sinks for signs of current or past leaks, and behind the shower (if available) and commode. As I said, good luck and happy camping!