Public transportation is your best bet. Van tour, hop-on hop-off tour, cable cars.
If you are not use to driving in heavy city traffic your best bet, first time in, is ferry (can be boarded at several locations), BART, or shuttle from RV park,if provided.
Get stuck in down town traffic it can sometimes take an hour or more to just go a few blocks (like 3 blocks). Though I use to drive in it everyday; you do not want to drive the Bay Bridge or Golden Gate during rush hour. The Golden Gate can be impossible on a nice weekend....dang tourists.
Have fun it is a great city.