Distance covered is one of the very best bits of GPS data available. It is easy to badly estimate, usually overestimating, the ground covered. If Mr.GPS says you have only walked one mile, don't lose heart because you have not encountered the trail junction at two miles. Inaccurate distance estimation if one of the main reasons people get confused.

I usually strap my GPS to my wrist when bike riding. It gives me great data on distance covered, and speed, etc.