Not sure about the weather in OCT, but I've been to SF a couple of months ago. How long are you going to be in for?
The city is really nice, it was a little different than some other major cities I've been to. I was wondering the streets quite a lot, and I don't recall seeing any gay people (acting out), though I was expecting to. I know it may sound weird, but with all the stories you hear and all, I thought I'll see them all over the place.
The downtown area isn't that huge, if you have the legs for it, you can do most of it by foot in a couple of hours.
Edit: Don't take the gay cable cars, they are retarded, and are a waste of time and money, I have no idea why I went on it in the first place.