There is no public transit options from the campground, lyft and uber are both unreliable at best. Your best bet is to drive your car (or rv) to bart in castro valley, then bart in from there. Warning: large vehicles occupying more than one parking space at bart will be ticketed, so consider parking your rv on a residential side street nearby.
I'm not sure of the bus that runs to the camp ground but Castro valley does have a Bart train station that will take you to San Francisco
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