Public transportation is your friend in San Francisco and Sandy and Deborah are big fans. This MUNI webpage is a good entry point for information about San Francisco's buses/cable car/light rail system, and for BART trains and ferries to get you to and from and around SF and the airports -- SFO and OAK. Also, the PresidioGO is a free shuttle worth checking out.

St. Mary's (the church where the wedding will be) is at the cross-section of two Muni bus lines -- the #45 and #22.