So, what do you expect from your rig AC? We have a 13k BTU AC in the front/master and a 15k BTU in the living. At present, the main 15k AC is keeping the rig at 10-12 degrees lower than the outside...
Yes when in the heat (i.e. South-TX), you must help the AC! We have insulated cabinets, put weather stripping inside storage access doors that are also accessible from the outside, used the insulated cushions for vents, caulked some areas, and cover some windows with the insulated foil type covers. Also switched to LED lighting as the 921 bulbs give out to much heat. Every little bit helps keep the unit cooler and makes the AC not work as hard.