An interesting drive is to go due west, south and west from Cairns highway 1. It goes from tropic to what looks rolling virginia hills to the arizona desert. I'm not big on nature trips and such but the changes are incredible. You can look across a couple hundred yards and see the change from semi-arid to arid. You go from tropical on the coast to what looks like temperate at the top of the hills. The road goes from two lane paved to one lane paved to one lane dirt. It's a major highway though, pull off with your windshield facing away when the road trains come through. Locals have roo bars for bumpers and screens on their windshields. They haul ***, once you see them you know where they got Mad Max ideas. You can see the dust plumes from a long way off. I found out about the drive heading to Georgetown to do some gold prospecting. There's lots of old stamp mills, boilers and iron stuff just lying around Gerogetown from the gold rush days. Those lines across the highway that say creek and river are sand. If you drive on the washboard roads at 10-15 miles an hour you will rattle your teeth out, speed up to 35-40 and you just get this brrrrrrrrr.
A 50 mile drive out of Cairns is enough to see all the landscape changes.
The Daintree area is supposed to be pretty neat for exploring and hiking, I didn't get up there. I heard on the news some girl got her stomach sliced open by a cassowary, a mean big *** bird, up there on a trail. It's still wild country.