Check wheel hubs for grease leaks and tires for unusual wear. Check the dates on the tires (DOT date codes). If approaching the 5 - 7 year mark, plan on replacing them. Look for any signs of delamination in the walls or water incursion inside around joints and seams. Make sure all the appliances work (must be plugged into shore power to test ACs and frig on 120V). As mentioned, GD has a good reputation for warranty service, but that unit is way beyond the warranty - you'll be on your own.
Rob