I did it, paying $3400/month rent & supporting a family. Salary took care of living + unexpected expenses, and stock grants/purchase plans took care of the saving + knowing where to keep the money (thanks, years of scraping by on non-SF-ludicrous pay packets).

edit I don't know what a 401k is good for (I already have two retirement saving schemes in other countries), mostly did staycations since SF is such a tourist destination.