If you have a bathroom with a vent or fan, I would suggest you install the Fantastic Fan there.
These are great fans, and move a lot of air. But they do still make noise.
If you install it where the bath fan is you will have 12 volts right there, and the noise wont be right over you.
I've put them in every truck camper we have owned, I switch them to exhaust and open the windows and vents around the bed. This draws in a nice breeze across you as you sleep.
Also if you have a source of water, you can spray or have a continuous flow of water to the outside of the camper (misting hose or sprinkler) you can remove some heat.
Also if you're traveling, stop and open up the windows. Try to keep the camper as cool as possible before you stop for the night.
It takes forever to get one cooled down that has been closed up all day rolling down the road.
Finally cool wet wash cloths, wipe down your skin, let the water evaporate.