Out of Livingston:

Carl with Safari Yellowstone, 1-800-safaris, will pick you up!

Out of Bozeman:

Let’s Go Adventure Tours and Transportation, 406-249-6816, will also pick you up!

Out of Gardiner:

Go to http://www.visitgardinermt.com and check out a listing for many tours.  These are just a few:  Yellowstone Wolf Tracker, Yellowstone Wonders, Yellowstone Year Round Safaris, Yellowstone Wild, plus many more.

Yellowstone National Park:

Full Day Bus Tour (you can get on at the Park Headquarters in Mammoth Hot Springs) through Xanterra:  http://www.YellowstoneNationalParkLodges.com and http://www.Reserve_YNP@xanterra.com