San Fran is a pretty big area with diverse areas. Do your homework on where you choose to live. There is definitely a lot to do there with kids. But the COL and creeps can be negatives.
My SIL/BIL live there with two kids they adopted. My BIL grew up in Marin. I lived several years in the City proper.
Not sure if this will work for you, but something to consider - If I moved back and worked in the City, I'd get an apartment as close to work/school as possible and just have one small car. San Fran and Chicago rank with NY in terms of being a true walking city and the BART system is pretty good.
