I'd suggest the Exploratorium science museum, but this may be a case of Typical Mind Fallacy. There's lots of museums in SF, so you should be able to find one targeting your interests.

If you're physically able to, you should walk across the Golden Gate Bridge and visit the visitor center.

If you know any employees, you may be able to get tours of different organizations. I was last in SF with a college professor who was able to get tours from his former students. There's not really much cost to just asking MIRI for permission to visit, even if you don't know anyone there.