Found
this card that includes a pass to Six Flags, a day pass to COPIA and a few other Wine Country activities, and tons of stuff in San Francisco itself.
A five-day pass is $119 and a three-day pass is $89. The question as always is of course, would I make a saving by using it?
A pity I didn't find it earlier, because they're having a sale that's ending today! But I doubt Akak and I could figure out its worth before the sale's end. One can hope that the sale extends a little bit more, or another one pops up a little later once we've figured out whether we want to buy it or not.
I emailed them to ask if the card can be used with Six Flags
Flash Passes. If Flash Passes are "incompatible" with it, then it would definitely be not worth it, as that's currently the most expensive and most inflexible (as in we MUST MUST MUST go!) part of our plan.
Will calculate worthiness later when itinerary is a bit more fixed. I've got tons of ideas for Wine Country, most of which is not part of the Go San Francisco card, but nothing at all in Medford, where the main attraction is definitely only Ee Lin's newborn baby.
Update: Discussed with Akak over the phone and the Internet regarding the card, and she got caught up with it when she realized it has a whale-watching tour. So we are after all gonna try to buy it today, and re-plan the trip around the card.
But when we tried to buy the cards, it wouldn't allow Malaysia. So Akak is going to try to get her Singaporean friend to buy the cards for us. See how that goes.