We have two young men here, ages 21 and 22 (grandson and friend) who are from Ohio. They want to see San Francisco sights such as Chinatown, Golden Gate, Alcatraz, ride trolleys, etc. Since parking is an issue, I have suggested they take BART, Trolley, bus for sight seeing. Does anyone know of a safe, inexpensive place these two on a limited budget could stay for about three days, keeping in mind that it be accessible to transportation?