An absolutely fantastic 'adventure' hike that may be done only in minus low tide conditions. It is described in the book "Point Reyes - Secret Places & Magic Moments" by Phil Arnot (1993, 224 pages). The route takes you through Elephant Rock, Elephant Cave, Ribbon Falls and Keyhole. About half of the route was along rocky beaches and half was along quiet sandy beaches. We had to wade in water using a hiking pole on three occasions. At one point, we were waist deep in water. The hike requires careful planning and execution. Phil's book has details. In May 2011, I joined a hike organized by Paul Grammens for the group 'North Bay Hikes'. According to Paul, very few days in an entire year allow this hike to be possible. Only a few of these days fall on weekends, so very few attempt this hike.
A low tide hike in Bolinas that goes about five miles along the Pacific Ocean. An interesting part of the hike is the scramble from Duxbury Reef Trail down to the beach at the start of the hike. A substantial portion of the hike is along paved roads.
An adventurous hike in Fort Ross Historic Park in Sonoma County. The route alternates between long rocky beaches and sandy beaches. The hike is feasible only in low tide conditions. Few people go along this route, so great solitude is available.
The hike is described in detail in Section 5 (Sonoma County, pages 184—187) of the book "Hiking the California Coastal Trail, Volume 1: Oregon to Monterey" (2nd Edition, 320 pages, 2002) by Bob Lorentzen and Richard Nichols. According to the authors,there are two spots that require low tide: about 1.5 miles into the hike, crossing a rocky spot requires tides lower than 3 ft; about 3 miles into the hike, a spot requires tides lower than 4.5 ft.