(Ignore my thread title, I mistakenly typed 6 weeks when this trip would be more like 3 weeks long)

I'm in the beginning stages of planning a trip to Australia next year in late-May, early-June. Was thinking of something like this:

Fly into Sydney for 4 nights
Brisbane for 4 nights
Surfers Paradise for 4 nights
Cairns for 4 nights
Darwin for 4 nights

I'd love to also see Perth and Melbourne but the weather at this time of year doesn't seem to be the best and since my current itinerary is moving up along the coast, I'd like to head to Indonesia from Darwin (Bali and Sulawesi) before flying back home. I've got 5 weeks total.

Does this seem reasonable? Any tweaks you would suggest?

Thanks!