Carlsbad (Legoland) can be a bit of a drive from many areas of San Diego. We stayed at a Hilton property next to the beach in Carlsbad last year, I think it was a Hilton Garden Inn. As a diamond we got breakfast. There’s a Costco nearby, and quite a few restaurants, McDonald's within a mile or so. This location did charge for parking ($10?), but I recall there being a Hampton Inn nearby that did not.

If you can split your stays between Carlsbad and San Diego, it can be quite nice.

There are multiple day passes for many activities sold online, and through Costco that may save you money. We bought a Legoland annual pass through Costco, for about the same price as a single entry ticket. It did have some blackout days for 2018/2019 between Christmas and the first few days of January.

https://www.smartdestinations.com/sa...Go&allInc=true

Our 5 year old loved Legoland, Balboa Park, and Ruben H Fleet Science Center. We only had a shorter stay in San Diego, so didn’t do Sea World or San Diego Zoo. I have been to them years ago and enjoyed them.