You are going the wrong way at the wrong time.
North during November onwards is the "wet" season. A lot of roads are closed, the cape, sometimes Darwin and other minor roads are also closed due to heavy persistent rain.
It is stinking hot at that time and 100% humidity, sometimes 110%. That is the time to be riding south, stay at the bottom half of the country and stay off bush tracks in the middle of nowhere. Think about checking out Tasmania as your start point, then the lower parts of Oz mainland, working your way north by about April, it will still be hot, and some roads may not be open still, but for a bonny lass from Scotland to attempt the heat of the outback in high summer, you may get a tad red!
I was traveling around north QLD and NT in September 2008 [url=http://travellingstrom.com/2008/08/31/]2008 August 31