If you are heading off in the next few weeks, monitor the road reports for possible flooding.
Otherwise, you should be on reasonable bitumen for the entire trip.
I've done Perth/Darwin in four days and Sydney/Darwin via Port Augusta and Alice Springs in four days in the last couple of years.
First in a 1.3 litre Honda Jazz. Second in a Subaru Outback. The Outback was more comfortable but the kangaroo bounced off the Jazz without leaving a mark.
Travelling after dusk is doable with care but not recommended for those of a nervous disposition or night blindness. Roos and cattle can be hard to spot, particularly in the glare of oncoming headlights or the ridiculously bright reflective signs they are in the habit of putting along the highways.
Stick to the speed limits even though the roads appear capable of higher speeds. Police appear in the most unexpected places.
Sorry I can't comment on your likely route through Queensland but I last drove that in 1978. But if you have time and want the scenic route try Sydney, Mildura, Port Augusta, Alice Springs, Katherine, Kunnunnurra.