I've used GPS before, like Google Maps, TomTom, and the like, but I've never used GPX tracks before. I want to ride the MABDR, and therefore need a good app for it. I downloaded the GPX file from the BDR website and then downloaded the GPX Viewer app from the Play Store on my phone. It appears to work okay, but I have no idea how to really test it out, as I'm not near the MABDR track currently. What apps do you guys recommend for following GPX tracks? I don't need to make my own tracks. I just need it to follow tracks already previously made.