We booked this tour through Expedia Local Experts. It included a 45 min. kayak trip from the boat launch to the hiking spot. We had a full group (actually, our group had somehow gotten overbooked by Duke's, so a huge family of 6 had to get kicked out of the tour), so we had to wait for some of the people in the group to all meet up together. The most important thing: bring water-shoes. Either the type of sandals that actually stays on your feet (not flip flops) with a strap around your ankle, or reef shoes. Because you're definitely going to get wet on the hike. And the trail was really muddy. You have to cross a couple rivers (the strongest/highest was thigh-high and the current was strong enough there was a rope for everyone to hold onto). Then you walk through some mostly-flat trails to get to Secret Falls. It appeared like there were 5 diff tour groups doing the same exact thing we were, so there were lots of kayaks, lots of people at the falls. Few people were actually swmming in the pool at the bottom of the falls when we were there - we did it, and it was fun, but the waterfall was so strong, you could barely see anything. A simple sandwich, chips, and 2 waters were provided for everyone. On the walk back, there was an awesome rope swing that the tour guide spent some time letting us use to jump into the river, that was the best part. :) Then we had to kayak back another 45 mins (with complaints from some of the weaker kayakers).
Overall a good trip. Sucks for the family that was overbooked, but our experience was fine. I was listening in, and it appeared that they were the ones that got cancelled because they just made a reservation, and paid when they checked in. Everyone else had pre-paid through another ticket sales company (either Boss Frog's or Expedia Local Experts). So the family that paid there was the one who got refunded. I believe that's why they got bumped. The rest of us couldn't have been refunded, because we didn't directly pay Duke's, we paid through other companies.