The last post finally said it...
The roof AC will cool the camper, insulated or bad insulated. How well insulated it is will determine how long or how often the Ac unit will run or come on. I had a black class-c and it stayed a meat locker in 115 deg desert in the sun.
Big windows will be big heat losses, but you can cover them when you are out or keep the shades lowered a little to reduce air from constantly circulating over a hot window.
The roof is a big source of heating too. Some roof coatings claim to keep the roof cooler, idk if true.
If you are at CG then AC compressor running all the time not an issue, note the fan will run 100% of the time, but if on a generator then the cycling will burn more gas.