Some other ideas in SF that I don't think have been mentioned. I have gone once or twice a year for at least 20 years. There are so many dimensions to what I consider one of the greatest cities in America. If you tell us what your interest areas are we might be able to make better suggestions:
- The Presidio. Military fort built by New Spain in 1776 and was a US Army post until 1989
- Golden Gate Park
-- California Academy of Sciences (a natural history museum)
-- Japanese Tea Garden
-- Bison paddock
-- Druid Circles
- Mansions on Nob Hill. The Stanford Court hotel was the HOME of Leland Stanford
- Bay model in Sausalito. This is an engineering model of the entire Bay that is still used to model flows, sedimentation, and so forth. Engineers will find it interesting.
- Cable car museum
- Alcatraz (get tickets now)
- Farmers market at the Ferry Building
- Chinatown of course
- Haight-Ashbury and the Grateful Dead House.
- Coit tower
- Golden fire hydrant - the only hydrant that worked in the Great Fire of 1906
- The cisterns. If you see a ring of red bricks in the paving of an intersection it is the location of the backup water supply. There are cisterns buried beneath the streets to provide an independent emergency water supply for (mostly) fire fighting.
There is a firefighting museum but I have never been there. But I did get to see a ladder company responding to a fire one time. SF uses "tiller trucks" that require a separate driver to steer the back of the truck to navigate narrow streets and tight turns. It's impressive but hardly something you can plan to see.
And be sure to watch
which is a short film made 4 days before the 1906 earthquake. You may recognize a few landmarks like the Ferry Building.