There are many options in NorCal for getting on track. Thankfully, there are 3 road courses in the area to choose from, Laguna Seca (Monterey), Sears Point (Sonoma), and Thunderhill (Willows). If you're concerned about runoff, pick the latter.
In addition to BMWCCA and searching up motorsportsreg as suggested by others, listed below in no particular order are a handful of orgs that put on NorCal HPDE type track days (I'm sure there are more).
https://www.speedsf.com/events
https://nasanorcal.com/hpde-get-started/
https://www.drivetracktime.com/
https://www.hookedondriving.com/hook...ion/California
https://trackmasters-racing.com/
https://americanracingclub.com/