I am bringing my sister and her granddaughter with me to San Diego Manchester Grand Hyatt while I am attending conference. They will sight see, with the two most distant destinations on their wish list being wildlife park and Legoland. It looks like car rental is cheaper if car is picked up at Hyatt, not airport. Hyatt charges $40 a day parking, nearby convention center surface lot doesn't allow overnight parking.

Uber, walking, bus will get them to most other destinations they have in mind: Balboa Park and museums, Midway, Children's museum, whale watch tour.

So, here is my question: what is most economical way to get them to Wildlife Park and Legoland? It looks to me like we will just need to rent a car at the Hertz location at hotel for two days so they can drive there and pay the Hyatt the parking fee. But am I missing something?

Thanks!