Needs overview and photo.
This is a multi use trail (horseback riders) that has great flowing singletrack. There are a few steep climbs but basically this is an easy ride. This is the best singletrack in the Seattle area accessible by taking the ferry from Fountleroy Terminal to Vashon Island. I'm posting this ride as a tourist to the area; I was guided to this trail by an islander. Here is a King County Parks link to a trail guide: your.kingcounty.gov/ftp/gis...
The route shown is not necessarily meant to be a route to be followed; it was just the route that I rode.