Best resource for Yellowstone

In my extensive preparation for our family road trip to Yellowstone, I purchased and studied at least a half-dozen books. Once we got to the park, this app was hands-down the most used and useful resource we had. It does not rely on wifi or a cellular connection. This is important, because there is no cell service in most areas of the park. The app can be set up to automatically narrate as you drive. It provides interesting information on the park in general, narration about specific sights, and information on worthwhile stops and side trips as you drive. There is plenty of notice of upcoming pull-outs and parking lots for the most worthwhile stops. We only had 4 days in the park, and this app helped us make the most of our time. I would tell anyone going to Yellowstone that this app is a must-have. Adults and young teens alike enjoyed listening to the narration. I have never reviewed an app before, but this was so helpful, I felt compelled to share.

Carolc1999 about Yellowstone GyPSy Guide Tour, v1.2