[twindman]

First, these Montanas are NOT insulated well to stop from heating up. I don't think there is even insulation in the top of the slides, as they are only about 3 inches thick.

Two points. I agree with those about running the A/C. Pretty much anywhere in AZ/NM/UT you will need it. And unless you are in the mountains in those states, you will need it all night. I live in AZ and if you are lucky, it gets down to 90 at night.

So in order to use the genny, you either need to be very strong - i checked and the 3000 weighs 140 lb (shipping wt anyway). Or get a 30 Amp extension cable and put the 50 and 30 together and just hook up to the 3000 in the truck bed.
I have stayed in Buena vista in CO that is around 8000 ft elevation. I would still need AC during the day time.
The northern states should be managable and beautiful.

p.s. off topic, but the Big Horns (WY) are my favorite area. Many boondocking places around there - some campgrounds with reservations and some dirt roads you can just park. Be wary of highway 14A on the west side, - it is called Oh My God hill for good reason. 10 miles of 10% and 8 miles of 8%. Not for the weak of heart. Oh, while exploring a dirt road there were a couple of campers parked. Withing 1/4 miles was a moose grazing!!!! Those are hard to find.