There are several IPhone and Android apps, but they only work where there you have cell service, and regardless of the marketing gimmicks, there are plenty places along the road where service is interrupted. I finally broke down and purchased a GPS that allows me to download specific trips including campgrounds, points of interest, fuel and food as well as repair shops along my route.
Planning my trip on my computer and the downloading it to my GPS works for me.
NOTE: I got the Rand McNally GPS at Camping World. It's the Good Sam edition and has a large 7" screen
2012 Newmar Ventana