Cairns?
Cairns? Great location and roads.
A little unnecessarily remote. By that I mean, if you go to WA, you gotta cross the country- that's where it is.
To go somewhere in Qld, you can just go to the Gold Coast (or Cameron's Corner, to make it fair for W.A.)
I'd be thinking Sunshine Coast Hinterland, since it's a good ride for everyone, yourself included.
And you can't fault the roads or the climate.
Need to be booking a Caravan Park
now if we want most of it!!
I also can't see a problem with going a week earlier to avoid the Ulysses AGM near-clash.