I flew into San Francisco on a Thursday. The first night I explored Haight Street, Fisherman’s Wharf, and the area I was staying--North Beach. I would recommend all. I was staying in the Green Tortoise Hostel. The place was great, but just know that it is near multiple strip clubs if that bothers you. The second night I went to a baseball game at Oracle Park, where the Giants play. It is an incredible stadium and I highly recommend it if you are interested in baseball.
Over the weekend I explored more of the town and saw most of the famous sights. That Sunday I went to the Haight-Ashbury Street Festival. There was lots of great music and interesting people. If you are in town during that weekend, it is definitely worth checking out.
In the evening I drove south with some people I met to Santa Cruz. We arrived late and stayed in a cheap motel. In the morning we went to a vegan breakfast place before going to the boardwalk (for which Santa Cruz is, in part, famous for). The boardwalk is nice and the beach and rocks around it are fun to explore.
In the evening we drove to Monterrey. This area is famous for 17 Mile Drive which is truly one of the most beautiful ocean views in the country. Another highly recommended place. We drove through it on the way to Big Sur, stopping at Bixby Bridge (which is also beautiful). Unfortunately we could only explore a little bit of Big Sur, but in the few hours we were there found an awesome natural swimming area and I know there is so much to explore there that it really warrants a few days at least. In the evening we drove back to Monterrey to sleep, and in the morning drove to San Jose where my flight was leaving from. There is tons of good Mexican food in San Jose and some decent hiking. It is a place worth exploring as well.