I second the mountain meadow cabins. The prices are extremely good, but only stay there if the only reason you're there is sledding. You need to sled up to the cabin (they help haul up gear), about 1/2 to 1 mile, and the nearest place to eat is the snowy mountain lodge, which is vaugley near where you park. You'll need to pack in most of your food, and bringing enough gas cans with gas to avoid having to go down the mountain to cenntenial is a good idea (usually snowy mountain lodge has gas). The two person cabins are pretty marginal to stay in, but the ones larger than that are great if a place to crash after riding is what your looking for.
Another place to consider is the Snowy Mountain Lodge itself, especially if you don't want to have to cook. The "trapper cabins" they have can be marginal from what I hear, so I'd go for a larger one.
The owners of both places are excellent. Mountain Meadow Cabins is a married couple, and the Snowy Mountain Lodge is owned by this horse breeding rancher guy who is quite the character.
Keep in mind both of these places are 10 miles away from Cenntenial, which itself is he definition of a "one horse town". If your sled breaks down and you need parts, you either rent a sled from Snowy Mountain Lodge or you go to Laramie for parts. This place is really only for hardcore snowmobiliers who wake up, eat, sled, eat, go to sleep.