Someone help me out with my Australia travel dilemma?

We have been planning a trip to Oz for a while now, but cannot make up our minds.
We are traveling with 2 kids (aged 2 and 5) in a small campervan with tent.
The timeperiod is roughly from the 1st of october till the 30th of november.

There are three scenarios we have in mind.
1. Travel from Brisbane to Thursday Island (north) and back.
2. Travel from Brisbane to Adelaide.
3. Travel from Perth to Broome.

Anyone have any advice?