Not necessarily from the area. However, look at the Big Basin State Park. It is beautiful there, and there's easy, covered hiking in the redwood forests.
26 miles Skyline to the Sea Trail, for its length it's a fairly easy DIAD hike.
Also, on the drive up highway 9 to Boulder Creek from Santa Cruz, on the way, there is a river along some train tracks, and beautiful swimming holes all up and down the river. It often has a dozen other people enjoying the area, but they mostly go to one spot. Plenty of serene spots that aren't hard to get to.