Taylor Park is a beautiful area. The reservoir sits at about 9300 feet, the surrounding mountains are 10-14000 feet. The weather there this past week has been with highs in the 80s, lows in the 60s. Yes, it can get crisp at night at that elevation, but in July it will be even warmer most of the time. You likely won't see 30s or 40s in July, and if you do, it will probably be just temporary.
Sounds like your setup will serve you well if you consider adding another battery. Batteries should be able to handle the heating needs, supplemented by your generator to recharge. I have a dual battery setup, no generator, and I'm good for 3-4 days easily with good electric management, saving the batteries to fire up the heater at night. As was suggested, set your heater to 60 degrees. In the unlikely event that you might need a propane refill, Buena Vista and Gunnison are not all that far away.
Thunder Mountain and some of the other folks who live over in that area may also be able to give you more info on specifics on the local weather and where to buy propane, should you need it.
