My husband and I drove from central QLD to Darwin ealier this year with our almost 7 year old 2 years and a bit and a 8 month old . I was stressing big time but really the boys were awesome. We took a DVD player but only put it on after our lunch break stop. In my opinion with a 6 hour trip some toys and plenty to drink and snack on you should be fine. I did take some baby einstein for our 8 month old when he became a little cranky and we simply were unable to stop and that kept him happy..

Goos Luck and travel Safe