I made some sunshades for a few windows in the camper. Here is one I made for the bottom bunk.
I used material for the part that faces inside, and reflectix for the part that faces outside.
Hoping it helps for the next trip.
We were fine on the first trip, but we were in a shady spot and he used a clip-on fan also.
Next time we leave, we will get the full sun.
We'll see how this works.