Most Australia trips land in Sydney for three to four days. You arrive, handle jet lag by walking the harbor, swim at Bondi or Manly, spend a morning at the Art Gallery of NSW or Australian Museum, eat at the restaurants around Barangaroo or Surry Hills. The Opera House and Harbour Bridge exist as geography and architecture, not mood. By day three you’ve covered the city’s functional core. There’s a domestic flight to either Brisbane (Reef connection) or the interior.
If heading north, Brisbane serves as transit hub. Most people overnight there, move to Cairns the next day, and spend two days on the Great Barrier Reef either via day tours, liveaboard boats, or island-based snorkeling. The Reef functions as singular experience: you go underwater, see coral and fish, assess your comfort level with the logistics. Back to Cairns, overnight, then back to Brisbane or continue south.
If heading inland instead, Sydney to Uluru is a flight to Alice Springs, then drive or tour to the rock. You watch the colour shift at sunrise or sunset (depending on which you book), learn the Indigenous history via guide, spend the evening at a resort. One night covers it. Then back to Alice Springs and back to Sydney or divert to another connection.
The third segment is secondary city or state variation. Melbourne offers galleries, laneways, coffee shops, restaurants. You spend two days there if you’re building in cultural experience. Or you fly to Hobart (Tasmania), spend time on the coast, visit Bruny Island for wildlife, eat at restaurants in the food scene. Adelaide works if wine region access matters. Perth if you want beaches and fewer crowds.