Agree with Hydroguy on the Airports. I would suggest SNA (John Wayne). It is closer and more convenient. Once your arrive at SNA you can get a shuttle or a taxi for around $40 one way, to your hotel. Then when you arrive at your Disney hotel everything you really need is within walking distance. Renting a car is almost usless unless you want to get out and explore the area a bit more.
As for going to L.A May I suggest looking into Southern California Grayline tours. They have this amazing Deluxe package for $96 USD per person, which gives you a full day at Universal studios (Your there for park opening), and then after park closing, you get back on your bus, which gives you a full L.A/Hollywood experience with a tour guide to boot, which points out celebrity houses, where certain movies were filmed, celebrity hang outs, where some celebs got busted for certain things, etc.
On this tour you will see such things as...
Trendy Melrose Avenue, Santa Monica Boulevard and Sunset Strip, home to such trendy spots as the Chateau Marmont Hotel, Whiskey A Go Go, House of Blues and much more! A stop at Hollywood Boulevard, offers time to explore the stars on the Walk of Fame and the foot and hand prints at Mann’s Chinese Theatre. Top off your evening with a quick photo stop at Downtown LA’s beautiful music center including the Disney Concert Hall.
Best thing about this tour is that transportation is included. The tour bus picks you up at your hotel, takes you to LA to do this entire Universal/Hollywood tour and then drives you right back to your Anaheim hotel, at the end of the day so you dont have to drive when your ran off your feet and totally exhausted. I have been on this tour a few times now and I would HIGHLY recommend it.