If you have the windows for it you would be surprised at how much a cheap window unit helps the roof air. Last year in the high 90's the combination kept our 30ft ball to bumper trailer very comfy in the low 70's..
Doing a test on it today solo without the roof air in direct sunlight. 87 out and 76 in without any foiled windows or doors, just the shades pulled with the indoor/outdoor thermometer in the rear.
Rated 4.8 amp draw and 515 watts on this particular 5k unit that cost less than $100 on special and runs great on my little Honda.
