If you know that you are traveling to San Francisco, you should book a tour of Alcatraz well in advance or discover the Napa Valley.
Alcatraz is a very popular destination, and with good reason. It has a unique and eerie atmosphere, especially in the night, and the audio guide provides a lot of fascinating information. If you are lucky, one of the former guards will be on duty.
North of San Francisco lies the Napa Valley, one of the best wine-growing regions in North America. There are many day trips from the city to taste the wines, enjoy a meal at one of the wineries, perhaps visit Oxbow Market, and dream about the lifestyle of a Californian wine maker.