At the heart of Rocky Mountain National Park is the 45-mile Trail Ridge Road,from late spring to mid-fall, when snow forces its closure. Traverse it by car from Estes Park (made famous by "The Shining") to Grand Lake or get out of the car to explore the 265,000 acres by foot, bike and horse or, in winter, snowshoe and ski. With more than 350 miles of trails, pick an easy day hike or a strenuous days hike that requires backpacking. You can also camp out, fish (mostly catch-and-release) or rock climb.