Two of the Bay Area's most popular hiking locales -- Castle Rock and Big Basin Redwoods state parks -- promise one of the region's top backpacking experiences. A three-day, 25-plus-mile hike through these parks from the crest of the Santa Cruz Mountains to the Pacific Ocean shows off everything to see in the South Bay woods, from the redwoods towering above to the banana slugs creeping along the forest floor. A popular version of this hike begins at the eastern terminus of the Skyline-to-the-Sea Trail, at the intersection of Highways 9 and 35 (Saratoga Gap). The first third of Skyline-to-the-Sea tracks along a highway and is otherwise unremarkable, so a superior option is to start from the Castle Rock State Park headquarters a few miles south of the gap on Highway 35. Castle Rock offers wonderful vistas of the mountains stretching to the sea, and a safe place to park your car. The second and third days of the hike traverse ancient redwoods in Big Basin Redwoods State Park, passing the impressive Berry Creek Falls and ending at the edge of America at Waddell Beach on the Pacific Ocean.