Thanks smiling cat. It's hard for us flat-landers (500 ft elev, here) to describe. I'll check the book and update. She just had a friend staying at the house with her get sick. We take the 6:00 am flight to Denver and drive straight up to the house. However, I think some of the renters do spend the night in Denver. I've tried those silly altitude vitamin packs and I swear they work!