We travelled by train up to Kuranda, and by Skyrail on the way back down. The train trip was great - spectacular scenery and a beautiful train. We upgraded to Gold Class, and would recommend doing so if your budget allows. As soon as we sat in our seats, we knew it was money very well spent. The seats were very comfortable and ensured everyone had an excellent view, and service, food and drinks were great. We heard people in the standard carriages complain that they were unable to see the view and were uncomfortable on the wooden benches.
The Skyrail back was great too, although there was a long queue to board. Coming back to Cairns via the Skyrail gives you a great sense of just how big the rainforest area is, and also gives you spectacular views of the coast.
The worst part of the day was Kuranda itself. We did not like the town at all - full of tacky souvenirs. We found the time there best spent doing the boat trip and walking through the rainforest rather than being in the town itself.