Okay...in Cairns you can:
1. Take the 100-year-old Kuranda Railway through Barron Gorge National Park.
2. Take the Skyrail - the world's largest gondola cableway through the rainforest
3. Take a cat out to Green Island and relax on the beach, go snorkelling etc.
These are the top 3 I'd suggest that aren't on your tour