Regarding the western slope of CO. You are going to have to get a lot higher than the 5000 feet that Grand Junction and Palisade (where we are) are at.
We have had low 90s to 100 degrees for weeks and the later part of summer is usually hotter than this part. The worst is yet to come!
The good news is that it does cool down at night to the high 60s or low 70s.
Also the swamp cooler (evaporative) will keep the house at 72 or 73 and the electrical bill is not affected much with that type of cooler.
Before we started our transition from full timing to snow birding we used to head to high country in Montana or Idaho in the summer.