RE cable cars: peteropny's advice is spot-on. That's what I always do, usually boarding around California Street where the Powell lines cross the California Street line. The Ghirardelli Square branch (running on Powell & Hyde) is definitely worth taking for the climb over Russian Hill. And it's far more interesting than the Fisherman's Wharf branch (running on Powell & Mason). N.B., however, that the signs for both branches say "Fisherman's Wharf" and "Powell & Market" at the top, which is where both originate. The one with yellow background and brown writing, the Bay & Taylor branch, really goes to Fisherman's, and it's not as interesting a ride as the other one. The one with brown background and yellow writing, the Hyde & Beach branch, goes over Russian Hill. The California Street line is often wide open, in terms of places to sit, stand, or hang off the car. It can take a painfully long time to come along, though, if you're boarding it in the middle of the line, up by the Mark Hopkins and the Fairmont.

The Hyde & Beach branch ends at a very pretty spot, right in front of the Buena Vista Cafe, where "Irish Coffee" was introduced to America. It's steps to Ghirardelli Square, unremarkable except for the chocolate "manufactory" that's worth a visit for any sweet tooth. Foodies would love Restaurant Gary Danko about a block away, widely considered among the best in the city. Probably too late to get ressie's now for Folsom Weekend.