Alternatives: Chain dog to outside of trailer and toss doggy pad/bed underneath trailer in shade. The ground will be 58-60f and dogs cool off by digging a hole or laying on the ground.
Keep doggy inside and provide air movement. Sucking out a small amount of air or a fan circulating air inside uses some of the cooler night time air that is inside the trailer in the morning.
Research how to mount a window A/C or an A/C split system into your trailer. The draw and current total will be less than a roof mounted RV A/C. You'll still need a generator or massive solar and batteries.
At 8600 ft elevation, you're probably going to encounter weather swings at shorter intervals. Also, the Summer season is shorter. Temperatures will be lower than at lower elevations. Research your area.
From your post, it seems like the dog's condition is paramount and not so much, the owner. A dog can get along in a lot more severe weather conditions than a human. Your doggo will probably be just fine if left outside where he can seek shade and cover from rain and snow. Have you thought about building him a doghouse? Dogs seem to always be more relaxed if they can lay/hang out in their own space.