I second that option of the CA Rail Pass!

A car rental with the drop-off charges would probably add up to much more than the cost of the pass. With the pass, you can take the train on the Surfliner from San Diago to LA, then connect to the Coast Starlight from LA to Oakland. (And possible more - as most Thruway buses and many other trains - are included!)

Best of all, the Coast Starlight for many miles travels in areas inaccessible to roads - so you could not see the coast any other way! And "someone else" will be doing the "driving", so all can enjoy the scenery, not the car in front!