This doesn't look like a mountain brike trail, but access to it is, due to a quirk in funding and land aquisition.  It is a completed section of the Foothills Trail between the Buckley and Orting segments,, but isolated from both.
Access begins at the end of the Buckley Foothills Trail.
The trail is muddy in spots,
and littered in others..
Then in the middle of nowhere, you come to this.
The first bridge you cross is the FEMA bridge, built by the Army Corps of Engineers in 1999,
and destroyed by a windstorm in November, 2014, cutting off access to the other three bridges.
The second is the Spiketon Bridge, crossing a small creek.
The triple arch bridge was partially constructed by volunteers.
The forth bridge is the old Northern Pacific trestle over South Prairie Creek.