Visiting San Diego next week

I am taking 2 kids to visit San Diego for spring break next week, on老朽 and others' sugeestion . I am flying to LA and driving down to San Diego.

I think we'd visit Universal Studio Hollywood while in LA. Would it take 2 days to cover all shows and rides there? Not planning on buying the express pass.

I will buy the Go San Diego Card for most of our stay in SD, but I still have the day driving from LA to SD unplanned. Is it possible to find something interesting to the kids to do at:

- La Jolla 

- Old Town

- little Italy

- downtown

- island of Coronado

Any any good place for meals? 

Many thanks!