I sell a lot of things on Craigslist including vehicles. The only hard advise I can offer is to include a phone number with texting capability. Do NOT EVER allow for email responses for you will get so much spam. If the person is serious enough, he or she will want to call you anyway.
I would state to any prospective buyer who comes to test drive your motor home, that you will drive it to a place where you feel comfortable for a test drive. This way he can experience the ride from a passenger's perspective as well as the driver's perspective.