Ok well here goes. This is just regurgitated thoughts so happy for anyone to start talking about best ways to do this. I will then start an itinerary and post again. Happy for any suggestions here.

X Fly to LA and stay at Anaheim do Disney, Universal Studios and walk of fame etc. think 3 days. Should I add another day for San Diego Seaworld?
X Go to Vegas. Not sure on how to get there yet. Fly or drive? Do Grand Canyon from here and Hoover Dam by hiring a car. thinking 3 days here.
X Fly or drive? to San Fran. Do Alcatraz, Golden Gate and other recommended. Not sure how long to stay here. Yosemite?
X Fly to New York. Do the tourist stuff. Any recommendations here? Bit lost for time and activities here.
X Now want to include Nashville Memphis Tennessee New Orleans if possible in some way.
X Florida Orlando Miami if possible
X Fly back to Australia. Not sure where from.