Sunscreen, chap stick, camera Credit card or cash Driver's License required Continental breakfast and lunch. Yellowstone is a very long day and not a great idea for young children. The best trips for kids are Granite Hot Springs and Gros Ventre. Most women are reluctant to drive, but once convinced, have a wonderful day. Snowmobiles are easy to operate.
Drivers are warmer, more comfortable, and have more fun than passengers.
Four people sharing 3 machines and taking turns works much better than four people on two machines. The increased cost is divided by everybody, and well worth the increased comfort and fun. Because of prep time and the need to travel by a vehicle to a trail head, setting aside a day to snowmobile makes good sense. If you try to ski and snowmobile the same day, you will shortchange yourself with both activities. In Yellowstone Park, you must have a driver's license or learner's permit to operate a snowmobile.