I don't know CoPilot so can't answer there. However I can comment on Google's My Tracks. It will track your path on the map and you can then follow it back to your starting point yourself. It does not provide a classic GPS function of giving guidance back to your starting point, but it does a fine job of tracking your route and the statistics. You can then generate a .gpx or .kml or other formats of the the data.
I used My Tracks on a recent hike and had my Garmin GPS along too. As expected, they matched nearly perfectly. As close as two GPS's would be. I was in the backcountry so no cell coverage. I turned the cell service, Wifi, Bluetooth off (put the phone in Airplane mode) and did a two mile hike. I figured the GPS would suck down my battery. I was amazed, only 10% used. Phone battery was still at 90% after 2 hours on a Moto Atrix.