We did Ca>Brice>Yellowstone>Glacier>Ca -15 nights, ask away!

There are a couple factors in these prices and it would be easy to do it cheaper. Some are for two sites, but primarily it is because I looked for the best long pull through resort sites I could find. We quickly found that we could not reliably reserve sites in the parks and we did not feel like risking our trip on the first come first serve system.