We have this app. and have used it to get from Utah to Ohio to TX and currently in AZ. The good points are ease in finding truck stops for gas, and for nearby overnight stops and for extended trip planning. However... it will run you right through the center of big cities like Jackson, MS; Houston; Dallas; San Antonio; etc. when the more sensible routes are the loop roads around them. In Tucson, it sent us through heavy traffic in a shopping area and told us to turn left at a "no left turn" intersection. We ended up on a tiny neighborhood street disconnecting our towed and doing some interesting maneuvers to get back onto the right route. Then, when we got to our destination (a state park); it took us well past the entrance which we only found by spotting it as we drove past. Another turn around ensued, and once again we had to disconnect the towed and left it disconnected till we got back to the park on our own. I cannot recommend this app.
I believe that for about 12 dollars a day you could hook up at the Snow Lodge at Old Faithful for high speed. Probably should count on having NO service. Maybe this could be a week of vacation from school?