Have 2 photo's of my House Air Conditioner in the RoadTrek, I made a front cover for it out of 1 inch Styrofoam, helps keep the back of the RT a little warmer in the Winter Time when traveling.
The Styrofoam was reasonable, found a small sheet of it behind a local Toy Store to be thrown out, so I cut it out to fit the House Air Conditioner, it is held up with 2 spring curtain rods.