Sounds like you'll have a blast! One big thing to see in SF (actually around SF) is Big Sur, it is an amazing place with gorgeous views, and you definitely want to check out the giant redwoods.
In SF, there's always the Golden Gate bridge and Fisherman's Wharf. If you are a fan of chocolate there's also the Ghiradelli Chocolate factory. Telegraph Hill is beautiful too and of course you want to hit the sidewinding street. I think that most of these things you can just explore on your own and so wouldn't have to book ahead of time.
Have a blast