Concerns for too few miles?

Always remember, rust never sleeps and most motorhomes sit on unpaved dirt or gravel pads and the moisture aspirates up and attacks the metal under side and gets into electrical connections. That may or may not be an issue.

Some people put on a lot of miles and some people don't. We used to drag the 5th wheel we recently sold on a 5100+ mile trip every year plus weekends away and often another week somewhere. Others just park them, trailers or coaches, and use them as vacation homes for the most part.

I would be much more concerned about how well it has been maintained than how much it was used. Whether driven or sitting maintenance is crucial! Ask to see the records.

I wouldn't consider that a problem at all. RV's sit more than they travel down the road. In 6 years, that unit traveled an average of just over 2,300 miles/year. That's more than I get to use mine, and as much or more as many others here use their coaches. And it seems like they may have only used the genset when driving down the road to keep the A/Cs running. If the coach looks in good shape, fits your camping style, and they have good maintenance records, you may just have found a gem!