a couple of years ago, i traveld from LA to SF (with a short stay in vegas)
in SF i stayed at a hostel in the redlight district in SF ... it was very close to "Pier 7". but i cant remember the name.
in SF, it was very easy for me to met other skates ... just skate at the famous spots and you will easly get to know some locals. i literally bumped inso some skaters from brasil, which i met in LA and we kept skateing together in SF.
but be aware, not every skater is your friend ... one of the guys from brasil told me a story that some other "skater" tried to steal stuff and money from them ... just watch out.