I agree with RhealNL completely.
Adding that any time you camp at elevation 8000 or higher, it can quickly become winter in the middle of summer. Many years ago my brother and I did an overnight back pack hike in the Tetons in the middle of August. We woke up to 4 to 5 inches of snow. We were concerned of missing the trail to get down from high elevation. Snow at elevation is not unheard of in summer, and the Million Dollar Highway is one such place where it can happen. So be sure your furnace is in tip-top shape, and your propane tank is full.....especially you diesel Sprinter folks with a propane generator.