Not too difficult to sell if it hasn't been moved - keep in mind, there's always someone looking for what they believe is a bargain. For the seller, if they think it's valuable, they'll take care of it and if they aren't taking care of the camper, they'll be happy to accept a lowball offer and save the annual seasonal fee
Getting a less that desirable neighbor on a seasonal site is no different than weekend camping. (Other than it might be longer than a weekend) If they deviate from the general population, make sure the campground management knows and do your part to invite them to find someplace else. Campground management pressure should be expected.
2014 Eagle Premier 331RETS
2016 Silverado 3500 DuraMax/Allison
1975 Corvette & a couple ATV's