Speed limit obviously varies, place to place. Near where I lived, it was 45 mph, but people regularly took it at 60 mph (much to the annoyance of the police, who naturally did their best to discourage such behavior).

I think it should run straight into both San Francisco and San Diego, but please don’t take my word for it; you should probably ask each of your friends, they’d know, and they also might know of quicker shortcuts (where I lived, PCH could become a parking lot at certain hours, so we would take other roads at those times).

Hope it helps.

Enjoy your trip.