Dunton Hot Springs

Here's a mining ghost town from the 1800s, restored into a small resort of hand-hewn log cabins at 8,850 feet in the San Juans, across the range from Telluride. Guests get a historic bathhouse and outdoor pools whose temperatures vary naturally, plus a small sulfuric geyser that goes off roughly every 45 minutes, more punctual than most trains. Everything is by reservation, year-round, through their booking engine. They mention day packages but publish no prices, so ask before you plan a day visit around it. The last stretch is dirt county road.