If you downloaded the route from the DLS, you can find his information on the DLS its self. Go to the web-based (white pages) DLS - see link above, and search for the route. His username will be clickable and you can then send him a PM. If he's still active, you will most likely receive a message back.
If you want to be bit brave, open the route for edit and view the config.txt file. In there maybe his email address which we hope is still active and you can email him. Once you've viewed the information, (copied hopefully to a text file), close the config.txt and revert the route to original.