The TravelMate site might help you to plan your drive:
http://www.travelmate.com.au/
The route planner,
http://www.travelmate.com.au/MapMaker/MapMaker .asp
gives the distance as 2484 km (1544 miles) and the driving time as 31 hours 22 minutes. If you're sharing the driving with others (and in a great rush) you could possibly do it in 2 days but, if you're in that much of a hurry, it would be simpler to fly.
Allowing 3 days for the journey would make the travel slightly less exhausting but it still wouldn't allow you to get to know any of the places that you're passing. (Once again, if you're not going to visit some places, en route, it would make more sense to fly).
4 days would seem to be the minimum 'sensible' time for the journey but 5 days might be better.
Unfortunately, I've not visited the eastern side of Oz, so I can't recommend anywhere to stay from personal experience. A quick web search, however, suggests that you might like to consider somewhere like Goondiwindi for one of your stops:
http://www.goondiwindi.org/
Chris