You may want to try putting a small AC through a sliding window if you have one. You can pick up a small unit for under $100, make a simple holder for it, and remove it while traveling. We put one permanently through the back wall of our former Burro
(lower left of the rear side, above the bed mattress), but it did take a lot of thought before I had the courage to cut the hole. I used our Dremel tool to cut it and it went very smoothly. I then built a metal shelf with legs attached to the back bumper so it was supported all the time. When traveling, we covered the unit with a Coleman cooler cut and carved out to fit over it. It looked like we were hauling cold drinks!
I've attached two pictures: someone else's window AC and our Burro
with the AC in the back wall.