How can i get to six flags discovery kingdom in vallejo, california if i live in san francisco, CA?

You do not take amtrak after the Bart trip. amtrak goes absolutely nowhere near Vallejo. Your best bet is to do one of two things. Bart/Bus method or Ferry/Bus Method: For Ferry/Bus: you can actually take the ferry from SF/Ferry Building right to Vallejo. Then there is a bus from the vallejo ferry building to Six Flags. It is Vallejo bus #85. it drops off across the street from Six Flags. The total cost for the bus and ferry ticket is $23.00 per person. Bart/Bus Method: You can also take bart from SF to the El Cerrito Del Norte Station and then transfer to bus VAllejo Bus #80 and then to #85 at thevallejo ferry building. For either method, there is a shuttle that runs every 15 minutes saturday, sunday and holidays only from the vallejo ferry building, otherwise bus #85 is the best bet. if you haven't already purchased the ticket for Six Flags, you can actually buy a bundled package with the park ticket and transportation via the blue and gold fleet at 415-705-5555.

Lisa H is right about Amtrak; To get to Marine World.. Err, Discovery Kingdom (I'm sorry, I was born and raised in Sacramento for 27+ years and will still call it Marine World no matter what! lol) via Amtrak, you would have to take a Capitols train to Martinez, and they have shuttle buses from Martinez to the park in Vallejo. www.511.org is your best bet for trip planning assistance.