I really don't have problem with ads. As much as I love building things, there is a definite opportunity cost that comes with spending time in front of the computer that could be spent, you know, actually hiking with my family.

The overall design looks very nice so Google adsense type ads would take away from that.

Have you thought about getting individual trails "sponsored" by a local outfitter? In the info box on the left side you could have Sponsored by Joes Outfitters with a link to their site, and it would match the rest of the text so it wouldn't even be that noticeable.