Driving South or North on the 5 is one way to go, but for the newbie or the environmentally friendly traveler there are other options.
Amtrak: Train routes along the coast, as well as through the central coast
Karen Brown’s Recommended Itinerary: Apparently there is a lady named Karen Brown who has come up with some nice itineraries of where to go and what to see and do. She started publishing travel books many years ago. Though the website looks old school, the content seems to be solid.
Megabus: For the budget traveler