Most importantly, if you are intent on staying at a Yellowstone campground, make your reservations well in advance. It is very unlikely that you will find a last-minute vacancy.

The area around Old Faithful is probably the busiest part of the park, just allow extra time if you are planning to visit that area.

The south entrance from Grand Teton and the east entrance from Cody are generally the least crazy. The West Yellowstone entrance is snarl of traffic during the peak season.

There is shopping, fuel, laundry and some repair services in both national parks. Cody, in the east, Jackson, to the south, and West Yellowstone, to the west, are the nearest towns offering a full array of entertainment and services.