Hi New to the forum, I'm Ray. Not sure if it is exactly what you looking for, but I use the mountain bike version of Runtastic app for iPhone. You can plot your own routes online or create a route from a previously ridden route. This then automatically uploads to the app. When you use this route it creates a grey line on the map on the app which you then follow, it unfortunately does not give voice turn by turn, you kinda have to keep an eye on the dot the represents you and where along the course you are. The image is from me seconding my wife in the CPT marathon yesterday, you can see where I went off route. This works the same off road. Hope this helps. http://s12.postimg.org/6mxf5dvl9/runtastic_mb_route.jpg