If we fly into San Francisco, visit your family in Modesto for a couple days (however long you/they want us there) - we could then fly down to LA/Hollywood and see all those attractions. Then from there rent a car for about 4/5 days and drive down to San Diego, stopping along the way at any of those beaches (Laguna, OC, haha) and ultimately ending in SD for a couple days and then flying out of there when we're done. And I feel like that area would be easier to navigate/you'd need a car to leave and try out different beaches, whereas we wouldn't want to deal with having a car in LA city mess.