We live in Utah County and drove in 2006 to DLR with 4 boys ages 18, 10, 4, and 2. We drove straight through, no hotel stays. Going to CA wasn't bad, just long and somewhat boring for our 2 youngest. Portable DVD players are the best.

However, coming home was the worst. We were all tired and cranky from too many late nights, too much junk food and hotel beds that aren't
our beds. My poor little boys were sleeping in car seats and were bent almost double. It was really sad. Also we hit a big snow storm around Cedar City and it wasn't pretty!
My DH and I flew to DLR for my birthday in Sept. 2007. Talk about a breeze! It was so nice to go to the airport, wait for a little while, hop on the plane and get to SNA. We weren't tired, we weren't cranky and it was soooo fast.
We have also driven in that same time frame (Oct. 2006 to Oct. 2007) to San Francisco and Seattle. I wouldn't do it again until my littles are at least 8. Then they could handle the car ride without booster car seats or bending half way over when they fall asleep.
We are flying to Burbank in 3 weeks!

With all 4 boys and grandparents and best friends. We got a deal on Delta for 139 round trip in to Burbank and we always rent a car anyway, so the drive to DLR is no big deal. Our oldest son is leaving for Taiwan for 2 years in April, so we are using our DLR time as some good family bonding before he leaves. It also helps that his best friends are our best friends children.
My ten cents. FLY, FLY, FLY. It is so fast and easy and so much less stressful for the body than being in a car for 9-11 hours.
Hope you have a really great trip. We plan on it!!