On Sunday, two weeks ago, I went hiking with several people from my lab in Mill Valley area. Beginning of our hike was pretty strenious - we had to climb 670 steps of the Dipsea Trail. But once we climbed the stairs, the trail became very easy - from then on we were mostly moving gradually downwards. All in all our hike was around 6.5 miles and took us around 4h (including picnic break). I thought that it was very beautiful and I would recommend it to anybody without hesitation.
On the road:

View from the top of the trail: