Sarah,
If you find (or think you found) the ideal motor home for you, ask on this forum and brand-specific forums if there is someone who lives near you, willing to show their rig to you. If convinced it is right for you, then order your rig direct with the factory, and finally fly out to the factory when your rig is ready, and drive it back home.
Irene and I got lucky. We stumbled on the one we wanted at a local RV show. Back then, we ordered our rig from a dealer in Mendon, MA a thousand miles away (called East Acres RV), and picked up our rig at the factory in Elkhart, IN 160 miles away.
New or used, if you can find the right rig at a local RV dealer, that is obviously most convenient. But typically your best used deals will be sold by private party. Craigslist, RV Trader, places like that are great internet shopping websites.
Ron