Thought I would post an update...
The house a/c will be replaced early Monday so we've been hanging out in the trailer in the afternoon/evening once the house gets too hot to be comfortable.
We have never tried to stay in the trailer while the temps are in the high 90s and our 13,500 Coleman/Mack is doing okay, but our trailer has 12 windows, 6 facing west/southwest. So, we went to Lowe's and bought a 24" x 25' roll of "Reflectix" foil insulation. Cut it just a smidgen larger than the window and rounded the corners to fit. Overlapped two lengths for the larger side window over the dinette. We are really impressed with the difference. Hopefully, the heat being reflected back onto the windows won't create a problem