If you don't want to rent a car, you will need to fly into SNA (John Wayne Airport). I THINK the resort offers shuttle service, but call them to double check. The resort does provide a shuttle to the closest beaches (Crystal Cove and Laguna) as well as to Fashion Island (local mall, open air, very nice). If you book local restaurants for dinner after 7pm, the shuttle will even take you there and back (Joe's Crab Shack, Garlic Joe's) so everyone can have a drink with dinner safely.
However, I do recommend renting a car, even for a few days, so you can go see local sights, esp. if you have never been to So Cal before. The way California is built, you will need a car (this coming from a former So Cal native.)Disneyland is close, L.A. sights are about an hour drive, San Diego about 90 mins. drive.