My wife and I just bought the small (read cheap) Garmin eTrex GPS to use on our hiking and kayaking trips. Anyone else used this one before? How user friendly is it going to be? Looks like it will be fairly easy to figure out. One question though for those of you that have used it... can I plan my trip out on the computer then punch in the lat/long before the trip or do I have to just hit the "Mark" button while I'm on the trip and save it for next time around?