We stayed a month at Red Rock CG at Island Park, ID, a few miles farther out than West Yellowstone. While we enjoyed the seclusion (and the wifi) at Red Rock, with fuel prices as they are I'd either be in Fishing Bridge or West Yellowstone (including the locale of Lion's Head) next time.
As noted, this is a huge, huge park. A hundred mile sightseeing day is not that unusual, never leaving the park.
Are you saying you want to see the geysers or Mammoth Hot Springs? The Hot Springs are worth seeing but we were somewhat disappointed in them. The geysers are awesome. See the ranger station for a schedule of eruptions. There are several far more spectacular than Old Faithful.
Our favorite part of the park is one that is often overlooked by tourists. The Grand Canyon of the Yellowstone area. Be sure to see the canyon and both upper and lower waterfalls.
If you have time, take the drive out the NE gate along the Beartooth Highway. Charles Kuralt called it the most beautiful drive in America. It is beautiful but I wouldn't call it the most beautiful. Still a gorgeous drive. Also, I hear the drive to Cody, WY, is beautiful although we didn't get to do that drive.
Drive south out of Yellowstone into Grand Tetons National Park. In a daytrip you can see most things. The Tetons are magnificent. And the lake... wow. Here's a picture Vicki took in 2005.
