I keep about a half dozen of the Giant Size fold-a-shade (the springy metallic foil window shades). These are stiffined with a wire around the perimeter, and the wire could be folded "around itself" for more compact storage. a pair of these is just the right size for the side windows, and the wire perimeter allow for enough spring that the adjust themselves to the front windows, also.
Open, they store nicely in the wasted space between the driver's seat and the front of the couch. Collapsed, they can be stored in an overhead, under the seats, or in the closet.
They are just the right size for ALL of the bedroom windows, also, and easy to move around as required.
Make sure you get the GIANT or Jumbo size with the reflective aluminum (like a space blanket), the regular large is not quite tall enough, and the painted or "scenery" material lets quite a bit of heat through.
Having at least one vent open on the top permits a lot of heat to escape via natural convection.
"Suck it up, spend the bucks, do it right the first time."
WBCCI # 1113
Trailer '78 31' Sovereign
Living Large at an Airstream Park on the Largest Lake Totally Contained in Texas
Texas Airstream Harbor, Inc.