Isn't it obvious that the OP is attempting to remedy his overwhelmed situation by seeking advice!
Give him (and the rest of us) a break!
X2. It's clear the OP is trying to become less overwhelmed by asking questions. It would have been much more productive to offer real insight.
The issue with older motorhomes that have low mileage is that it could indicate it has sat for long periods of time, which is not good for any motor vehicle. Sometimes it means they just didn't drive very far. A thorough check by a trusted mechanic as stated above is a good place to start. Ask for service records as well.