Check out 48-hour guides to Colorado’s national parks here: Rocky Mountain National Park Great Sand Dunes Black Canyon of the Gunnison Mesa Verde The Rockies will have a home game against Philadelphia and the Nuggets will be at San Antonio for Game 4 of their playoff series, but Saturday might be a good day to get out of town and celebrate the grandeur of Rocky Mountain National Park. Admission will be free there, and at all national parks, on Saturday to mark the beginning of National Park Week.