149oaks, it was a bit of a brain dump
I wouldn't expect you'd get to see all or even half of that. I guess I am saying, pick and plan. There would definitely be traffic in but if it was me, I wouldn't use a taxi - expense and is it likely to be much faster? - I'd get the
BART into the city. I just checked for New Year's Eve morning and there is
Return service in the afternoon is the same. I assumed an arrival time back at the airport of 3.
Get a guide book, mark off a few things, plan the routes and adjust until you have a feasible trip. The nice thing about San Fran is that the Cable Cars and the Street Trolleys are in themselves a great tourist experience
Something like this might work for you...
BART to Powell, Cable car to either Mason or Hyde (perhaps a stop off at the Cable car Museum en route). That will bring you down to Fisherman's Wharf (if you want to spend time there then that would be the time to do it) Street Car to Embarcadero, Cable Car up California to Chinatown, have a wander there, then walk back down to California to catch the BART back to SFO.