This is a bit late, but for future reference, I just spent time with some folks that stayed at the Adelaide in downtown SF. They said it was fine for their needs, tho it is not the nicest/most scenic area:http://www.adelaidehostel.com/html/index.htm
Sounded like at least the Adelaide guests (and possibly other hostels) get a discount at Blazing Saddles:http://www.blazingsaddles.com/
My friends said they would tell other people to take the bike ride to Sausalito and the ferry back.
BTW, I also took them to Muir Woods super early in the morning, and that was a big hit as well. Hard to get there during the week w/out a car & during the off-season, but weekends during tourist season there is a bus connection:http://www.nps.gov/muwo/index.htm
Dont rent a car for visiting SF city, though. you'll make yourself crazy and poor trying to avoid tickets. One of the other folks at the hostel had just gotten a fat ticket for not curbing his wheels (to prevent runaway autos) properly on a hill.