Well you stopping at mission bay which is close to Seaword......theres the world famous san diego zoo,Balboa park also worth a visit we went to the aerospace museum but other attractions there.....plus the Coronado hotel is worth a visit if you can get there..
we stopped at the gaslight quarter and it was very expensive for food and drinks....found out later its one of the most expensive citys in USA so you may find things more expensive than LA,depending where you stopping there.

Balboa Park and the zoo very much worth a visit. Try the trolley tour and duck tour (use google) which will help you get your bearings. The trolley tour's second stop on Coronado is at the hotel. Beware if you get off the trolley at this stop in late afternoon you will probably have a long wait to get available seats on later trolleys.

The climate in San Diego is wonderful....never too hot/cold and usually a sea breeze.

We did a similar holiday itinerary this year. Los Angeles (Long Beach) then San Diego (Mission Bay as well - the Hilton) then on to Las Vegas.

As others have said, Seaworld, San Diego Zoo, Balboa Park, Gas Lamp Quarter all worth a visit. We also went onto the Midway aircraft carrier.

For further information why not check out the San Diego Visitors Bureau website http://www.sandiego.org/nav/Visitors