One of the great things about San Jose is that you can get out of town rather quickly, compared to places like New York, Chicago, or Los Angeles. About 20 minutes from our home is Castle Rock State Park, on Highway 35 which runs along the spine of the peninsula with the S.F. Bay on one side and the Pacific Ocean on the other.
You can park on the highway during the day at no charge. Inside the park there is a day use fee and also for overnight camping (walk in only). A lot of people come here for rock climbing and to practice rappeling. From the parking lot it's a mild downhill hike to the overlook and on down to the camp site. If you are really in good shape you can hike all the way to the Pacific. If not, you can at least get a pretty good view of the wilderness and if the fog has burned off, the ocean.
A good map of the park is here.