During the car drive, the driving side alternates between left hand drive and right hand drive.
At the first fuel stop, when Lisa comes out of the shop with the petrol can, Wade is filling the car on the drivers side. The flap on the petrol filler is on the other side of the car.
When talking about changing the itinerary to go to Uluru from Sydney, instead of heading up the coast, she says they can see the big pineapple, the big windmill and mad max museum... The Big Pineapple is about 1000km North of Sydney in Queensland and not the direction to Uluru, especially if they are going past mad max museum in the outback route.