We had been planning to visit the Caves for a couple of summers now, and we're wishing we hadn't waited so long!
They offer flashlights if you forget to bring one, and walking sticks to use. Take the stick! Quite helpful for balance on those tricky narrow spots and for steadying yourself on the wobbly rocks.
Make sure you wear sturdy shoes or boots with good treads as the rocks can be a bit slick in some spots. Nothing dangerous if you're careful though. There are no safety rails or ropes, but they're not really needed in most places.
The gent at the gate was very friendly and recommended the second trail for the views. We were glad we took his advice, because the view from the lookouts are spectacular! We had a clear sunny day, so we could see for miles out across the water.
My only wish would be if they could mark somehow where the movies have been filmed. A discrete number or mark somewhere for reference would be good, just to put in perspective where certain scenes were shot.