A few weeks ago I set out to run from Stinson to Muir Woods and back on the famous Dipsea Trail in preparation for the race I ran at Armstrong Redwoods. The total distance was just under 13 miles, with a total ascent of 2800 feet. I love the trails on Mt. Tam, you get to see so many different micro climates in such a short distance. The trail winds through open grassy fields, redwoods, bay and oak forests, and panoramic views of the Bay.
I had never done this trail before, despite being a native, so I looked it up on ProTrails.com. I would suggest if anyone wants to try this trail, however, to start at Stinson rather than Muir Woods because on weekends it is virtually impossible to park in Muir Woods and usually you have to take a shuttle in. I opted rather to park at Stinson beach, run the distance and back, and then had a relaxing couple hours refueling, re-hydrating, and sun-soaking on the beach. Oh, and napping. Always nap when you visit the beach.
If you aren't game for a mega-hike, you can also break this trip down into smaller legs. I sometimes really enjoy starting at Pan Toll at the top of the mountain and hiking Steep Ravine trail down to Stinson. It's all downhill, and at the end you can either hike back up, take the bus back up, or hitchhike. Don't forget to get a soft serve at The Parkside.