A definite must have!!
This more than met our expectations. Not only does it track your driving and tell you whats coming up, but it gives you information about it. It tells you about must stops about how long it will take but also gives you other suggestions. If that wasnt enough it even gives you history about the park, the animals, and geology. I am so thankful I found this. You do have to download it before you go. There is basically no service inside Yellowstone. The app fully downloads the map and all the data it needs to run without cell or data reception. Cant say it enough how much this increased our enjoyment of the park.
Teddv about
Yellowstone GyPSy Guide Tour