It's very easy to get into Colter Bay campground. It usually doesn't fill up until later in the day, if at all. Most of the sites will allow generator during proper hours but don't have water or sewer. One loop does now have electricity on very large spots, but mostly for handicapped campers, although if not taken later in the day, they will rent to regular people. Colter Bay is about 45-50 minutes from the South entrance to Yellowstone and a person can see Yellowstone from Colter Bay, it just takes a bit of driving. We usually get up pretty early and sightsee in Yellowstone for the day and then get back to Colter Bay pretty late in the evening for a nice meal in one of the prettiest spots we have ever seen. Unless you are an avid hiker and just have to hike all over the place, a person can take two to three days and see most of Yellowstone that can been seen from a drive. The lower loop takes you to Yellowstone Lake, Canyon, over to Norris, down to Old Faithful and then back south to Grand Teton. The upper loop goes over Dunraven, over around Lamar, up to Mammoth and then back down to Norris, Old Faithful and back to Grand Teton. Yes, there is a lot of mileage and a lot of animal jams, but why get in a hurry, you are in a part of the world that is wondrous and spell-binding. Just take your time and enjoy. As for Grand Teton and Colter Bay, it is a beautiful place and you can take a cruise on Jackson Lake on the marina cruise boats, drive around the Park and see Jenny Lake which is beautiful, hike to Hidden Falls on the other side of Jenny, go over to Moose Junction to the Craig Thomas Visitor Center, drive over to Gros Ventre to see the results of one of the largest landslides in history, and look everywhere for wildlife, it's there if you are lucky. Have a great trip!!!!!! By the way, if you have the Senior Pass for national parks, the campground cost, for the non-electric sites, will run you about $12 per day, what a bargain.