From the third week of December to the first of March, Gary Fales Outfitting offers guided snowmobile tours through the east entrance into Yellowstone National Park. They offer daily or overnight tours. The all-day tour includes Old Faithful, the Geyser Basin areas, Yellowstone Falls and Yellowstone Lake. There are also many opportunities to view the wildlife in the park. Trips can be customized to fit your needs. They also offer snowmobile rentals for self-guided tours.