Dont let inside get hot, then turn AC on to cool it off
You must let the AC get a head start on getting the inside cool, before the big afternoon heat develops.
Use a box fan to help circulate the cooled air.
I had a 28' toy hauler...1 15k Dometic...it worked as well as could be expected in the sunny mid 90s degree days..once sun went down...it make the inside a meat locker
96 Dynasty 36' that does NOT wander, thanks to RuppParts.com and their superior "poly" suspension bushings