Thanks for the tips. I have amex plat but will be in T2 and with late flight at 11pm, don't know if time allows me to go to the amex lounge and back, plus it closes pretty early I think.
Getting from the Amex Cent (T3) to AS (T2) doesn't take long, especially if you have TSA Pre. Without it, then it may be a problem, since I'd wager at around 7 pm - 8pm, the SFO Centurion should be pretty packed. Hopefully, if you're lucky, it won't too busy, which you should have ample time.
Would it be better to hit up the bridge and palace around noon first then come back to union square area? I'm assuming both places are just quick photo then go, so 30 minute to an hour or so?
I'd probably have lunch when exiting BART (Powell or Montgomery), then take Uber/Lyft to the Place/GG area, then head to Pier 39 from there, and track back to Union Square to MOMA.