Lived in San Diego for 5 years. Met my wife and got married there. My wife is from Santa Barbara. You'll swing by there on your drive south. If you are looking for things to do in San Diego, here are some of my favorites.
San Diego Zoo
Balboa Park
Old Town Mexican Cafe (in Old Town). Fantastic food and not too expensive.
Pacific Beach, especially if its hot. Rent a surf board and catch some easy waves on the north side of the pier. They also offer lessons for the kids.
Padres game at Petco Park is a great venue as well.
Mt Soledad. Really great views and a tough little mile long hike that starts and ends at the veterans memorial. If its hot, pass on this. But a great place to watch a sunset.
Tour USS Midway aircraft carrier. There's a great Seafood place right next door called Top of the Market. I proposed to my wife after having dinner there.
Hotel del Coronado has a phenomenal brunch on Sundays in their Crown Room. You can watch the Navy SEALs BUDs class trying to bring their boats up on the rock jetty right next door if they have a class in session.