I'm actually a three-hour drive from SF. And I have to say, if I were in your shoes, I'd say the PCH drives would be a better choice than a Tahoe trip. We like to do the PCH drive about once a year, down to Morro Bay and back. Very nice. Make sure to look out for cresting whales off the extremely high cliffs just north of San Simeon. (If you go that far south from San Fran, you might not...)