3300km.... lucky you.
I took mine to Newcastle - Townsville and back when they were about that age and they traveled really well.
The main thing is to take breaks to they can get out of the car and explore stuff and burn off some energy. Snacks, pencils, paper and something to draw on can keep the older one entertained. Wiggles singalongs kept them amused, but sent me out of my mind.
We were lucky that the eldest sleeps within 10 minutes of starting the motor, now 14 and nothing has changed. The youngest talks incessantly.
Things to see, at that age you can make great plans to see sights, but they will probably enjoy poking a stick in a puddle or rolling down a grassy hill more than any tourist draw card.