Start at the Pine Creek campground, about one mile south of the town of Pine Creek on the East River Road, to hike the popular and lovely trail up Pine Creek. Pine Creek Falls is just a short hike from the campground; Pine Creek Lake is another three or four steep miles up the mountain.
Mill Creek reaches into the Absaroka-Beartooth Wilderness Area [1]. The lower stretches of Mill Creek Road, heading east from the town of Pray to the wilderness boundary, are good for mountain biking, and the foot trail continues into the wilderness area. Thompson Lake, Elbow Lake, Mt. Cowan, and Passage Creek Falls are some of the destinations for hikers. Snow Bank campground is a handy jumping-off point.
In the Gallatin Range, hike or cross-country ski just about any drainage: Trail Creek (there’s cross-country skiing near the Forest Service cabin); Big Creek (28 miles south of Livingston [2], then west up Big Creek Road, trailhead is across from Mountain Sky Ranch); or Rock Creek (with access to a trail network).
The hike up Tom Miner Basin starts at the Tom Miner campground and includes an interpretive trail in the Gallatin Petrified Forest. To reach the trailhead, turn west off Highway 89 between mile markers 16 and 17 onto Tom Miner Creek Road. Follow signs to the campground, approximately 12 miles from the highway. The petrified forest trail is about two miles round-trip.
Links:
[1] http://www.moon.com/destinations/montana/the-missouri-headwaters-and-south-central-montana/absaroka-beartooth-wilderness
[2] http://www.moon.com/destinations/montana/the-missouri-headwaters-and-south-central-montana/livingston-and-the-paradise-valley/livingston