Ten + year old RV's with fairly low mileage are a large red flag. These units have been used very little and ignored a lot. Pumps, bells and whistles do far better if they are used on a regular basis. Whatever you get serious about check the manufacture dates of the tires as they time out at about 6 years vs the actual miles on them. A new set of shoes for a C is $1200 to $1500. If you find even the tiniest hint of water damage "Run Forrest Run!"
The bottom line always comes down to getting what you pay for. While not a fan of buy a rental many here are. I've just seen way too much abuse by renters to ever consider buying a rental. The good news is there are lots of very nice C's out there so take your time and enjoy the process. Good luck!
:C