Thanks for all your info and help.
We have decided not to drive. Even though its tempting, after a big flight with 3 kids, we will be a bit frazzled!
Thinking about southwest as an option, with the ability to change the flights if available.
How does southwest work? Do you need to check in by a certain time? I dont think we have a similar service in Australia, at least not one that i have used.
thanks