Ripsnort - to answer your question - go with eagl's advice... Call your company. If it was a car, I'd think you'd probably be good to go, but I have no idea what the language is like for RV's... Also, every state is different, so we're all pretty much useless.
Take the name of the person who called you and record the call if you're really worried.
Regardless of what your policy says, if something happens (from the most minor fender bender upward) expect to get a letter from an attorney saying something along the lines of:
"This office represents Mr. John Doe who was injured and whose vehicle was damaged in a motor vehicle accident when [your friend], driving a vehicle owned by you, collided with his vehicle. This accident occurred on such and such a date at such and such a place. Please turn this letter over to your insurance company for proper handling."
The reason you purchase insurance is so that if you get this letter, you have someone to defend you... This is the "product" insurance companies sell. If they don't adequately defend you, you have a bad faith claim against them.
As an aside, please realize that people like AKhog exist (with no facts, but many years experience, I'd say they're likely a majority), and when they cause an accident that causes you to have more damages than their policy covers, you had better either have a very strong underinsured motorist policy, or pray to your deity of choice that AKhog actually has assets that can cover your loss. Otherwise, you're screwed.