Cycling/Run/Cycling: 24M on the bike and 7M sweet sweet trail miles
Ride: SF->Miwok Trailhead (@ Shoreline)
Run: Miwok Trailhead->Miwok (->Miwok Cutoff->Tennessee Valley->Fox->Coyote Ridge->Miwok->Miwok Trailhead
Ride: back home.
If you’re wondering where to lock that expensive road bike you rode to the Miwok Trailhead, consider that with a cable lock one could actually secure a bike to an enormous eucalyptus tree somewhere back in the woods a bit…
There’s also a moderately secret ridgeline finish that takes you back to the trailhead. On your way back, stay left and high, even when it looks improbable, and you’ll find it. Recommended.
An alternative run (longer, definitely more brutal): from the same pullout, cross the 101 north to pick up Miwok (in to Mt. Tam rather than the Marin Headlands, and take Dias Ridge Trail down in to Muir Beach and back again.