Hi Vicki
You've really planned a great road trip. One suggestion, if you're a member of an auto club in Australia check to see if they have an agreement with the AAA here. AAA is great for maps, guidebooks, etc., plus many hotels/motels while not offering an airline rate will offer AAA rates. AAA guidebooks I never start a road trip without them.

Oh, when you see an In-N-Out Burger restaurant, stop; great burgers and fries.

Keep'em flying