Cairns is the classic Far North Queensland base for reef days, rainforest escapes, and easy day trips. Start with a Great Barrier Reef cruise or snorkel tour, then leave time for the Esplanade lagoon and a sunset wander along the waterfront.
If you want green scenery inland, Kuranda, the Atherton Tablelands, and Daintree day trips are all doable from town. Mix one big water day with one rainforest day and you will cover the highlights without rushing.