When is the trip planned for ?
Summer is cyclone time up here and screamingly hot and steamy.
Winter in the south would not be that different from Europe !
I would look at spending some time based in or near Cairns if at all possible for rainforest and reef trips.
I would try to get to Uluru and the red center and then probably some time in Sydney or Melbourne to see a city if possible.
I prefer to spend time in a couple of areas having a good look than spending all the time rushing from place to place glimpsing lots of little bits of stuff.
"Photography to the amateur is recreation, to the professional it is work, and hard work too, no matter how pleasurable it may be."
( Total NIKON bigot )