The ac in the 31' tt we had would freeze us out and it was only one unit. I would say to get another ac if you are worried about it. But if you are in the sun, then yes it will run a lot. With the motorhome(also 31') it would continuously ran until night time while at the beach. During the day it would only get to about 87 degrees at the most, but we were in direct sun.
I'm against covering the windows with things like reflectix. I want light coming into the camper and don't like the look of it in windows on the outside. Sme have also reported issues with certain windows and reflectix.