This was a great tour. We went into the Waipio Valley with our tour guide, who was great. We crossed streams, looked at unbelievable vistas, and swam in a pool with a waterfall. It was a very cold and rainy day, though, not the ultimate conditions. But we decided that we would take a dip because my son and I didn't know when we would be back. I do recommend a backpack with either sandals or water moccasins, because the entrance to the waterfalls is rocky and it HURTS! Other than this, we had a great time.
Our guide took us through unbelievable forests that used to be sugarcane fields. It is amazing the amount of history that surrounds this area. The lush tropical atmosphere is tremendous.
The tour provided water and a sack lunch; it wasn't Cordon Bleu, but when you're hungry after hiking a few hours, it tasted just fine. I would definitely do this tour again. It was pretty easy as long as you are in somewhat decent shape and are ambulatory. This tour is not tough, but not for anyone with heart conditions either. If you bring a camera that you value, either bring a waterproof case or a baggy that you can seal it in.