貪多。Lego 2-day; Balboa/Zoo 1-day, Seaworld 1-2 day. 住oldtown cour

Old town is not a specific place for kids.
Kids love Legoland, there is a aquarium/water park so buy a 2-day pass for all they will want to be there for ever.
Renting a car is cheap in San a Diego. Remember bring your car seat and booster to save you money.
old Town is a good place to stay, it's convenient to all the places.
Courtyard has daily bus to Seaworld, and Zoo if you donot want to drive.
Westin at the valley hotel loop is also excellent.