My 2008 30 WRLS W/O Atrium slide but two slide outs has a 13,500 ducted Dometic AC that cycles on and off in 94 degree days in Florida, and we set it at 72 degrees- works great never any complaints. However, AC units are designed to cool 20 degrees below the outside temperature; so at 92 it should cool to 72, but not much more. Set at 73, it would be having to work pretty hard in full sun with all those windows. By the way, a 15,000 btu unit is as big as they get; your only opeion would be to add a second unit for more coolness, however that would require some major upgrading to your converter and power supply for 30 to 50 amps for 2 units. Best thing to do is find a shadier campground, or camp when it is cooler outside, or use fans to add to the AC's breezes.
Good Luck, Randy
/SIGPIC]'08 V-lite Flagstaff 30WRLS
'06 Ram 1500 QC hemi
Reese dual cam sway control,
K&N series 77 intake, Hellwig helper spgs. LT tires,
Flowmaster "true duals", 380 h.p., Bilstein shocks