Download avenza maps its available for droid and iphone. You can download any map and save it to your phone and access it without cell service. If your phone has a gps you can pull up the map plot tracks measure distances and more. Its a free program. What i usually do is go to the usfs site of where we are going to ride and download there topo off trail maps or whatever forest service map that has all the roads and 2 tracks on it. I have garmin rhino 650's and to be honest use the avenza on my iphone more.
