Here's possible warning signs of leaks .
New roof vents and hoods. Were they hail damaged or other problem?
Any time you see a vent was repaired for Minor Leak, that's telling you they never noticed the leak till someone was getting a face full of rain while camping. OR they saw a pool of water on blankets etc. When a vent leaks the water usually travels down the interior space between roof and walls of camper. A leak may be found as far away as the opposite wall. From the many campers we have purchased (and sold by labor day) plus the many EXCELLENT CONDITION (minor leak repaired) units, i'd suggest a thorough inspection of the interior, including floor to wall sections etc.
Next item, anything over 19-20 are boat anchors with over priced tags on them. Who pays seasonal full boat on something that should be winterized and in storage? Might as well buy a used (approx 1K rounds) AR for $1200 instead new for $900.
Those tandem 20"+ units will be there in dec, jan & feb. Look around now, make notes on units viewed, then again come jan &, feb. That's going in to prime buying time.
Remember first one who talks, Looses.