I will be making a quick visit to Northern Australia next month, stopping in Darwin and Cairns. My initial plan was to fly to Bali after for 10 days but I was wondering if it would be worth adding Brisbane or Perth to my itinerary?

Brisbane is a long flight to Bali so I'm not sure about that one... I probably won't be back in Australia for a couple years after that so this is why part of me wants to see as many cities as possible but at the same time, I don't want to travel too much between places.

I've already been to Sydney and loved it.

Any input is appreciated.