which would be the best for me? everyone has actual GPS units in their jeeps but when I go out there, I have no cell reception. I have a 3Gs and know it has a good compass app. the thing is, when I was out last time and got lost, it pointed my coordinates to the wrong hemisphere. so I would like something to keep logs of where I go, so that I can view them and see what trails I went on. I am in florida, so there isnt much terrain, but where I go, I have no cell coverage. please help.. but would it keep a good gps trail with no cell coverage?