Graham replied:

If leaving early May then I'd be going up thru the centre, as I'd want to be up north for the cooler months then head down the west coast August September. So maybe May around Alice area, then June Darwin, July Kimberlys/Kununurra then Broome/Karrartha for August then September down to Perth area & home. 6 months won't give you much time to hangabout, I'd like 9 to 12 months for the trip, it depends on how long you want to stop in places for..

cya

Snake replied:

Graham,
We as a family headed off for six months, (March-September) Mum /Dad and an 8 and 6 year old from central Vic in 1995. We should have, looking back spent the six months in W/A. The problem we found was not knowing what was ahead but just wanting to explore. Advise! Take your time and plan more than one trip.
P.S I still am but we will!

Mudguts replied:

G'day Mark,

I certainly follow Graham's advice and go north in May rather than west to avoid the cold.
You'll also find travelling will largely be withthe wind rather than against it and if you want to see the south west coast of WA it will be
much more pleasant whether in Sept/Oct than May June down there. Leaving early to mid May will put you ahead of "the pack" and
you should find most roads open and accommodation bookings not as busy. You will also get you into WA as the wildflowers are blooming at their best as you go south.
In six months you'll have time to see a hell of a lot without too much backtracking.
Have a look at our trip report on a similar trip in 2000 on Gerry Roffeys site http://www.geocities.com/flourpower.geo/caravan.htm

Its not meant to be the recipe for all but it might give you a hint or two

Good luck Ron