Here's an idea -- check out some of the GPS athlete sites where people upload tracks and routes from their bike rides/jogging trips/etc. to pull up opportunities in your area.
Here are a few:
*
http://www.motionbased.com/
*
http://bonesinmotion.com/
There are more but my addled brain is forgetting them. I'll pick Justin's brain and add more if they occur to us.