Also, most of the hikers are in a group, there should be a way to create a group tied to a specific area.
Finally, you should think of something better than donations to keep this going, because potentially it can go very far. The thing is you are hosting pictures, can't you use an external provider (flikr, picasa)? Otherwise, if you reach an important size (and for this site, you have to), even a supporter budge (a la couchsurfing) for $5 a year could bring you nice revenues.