This is now 2 separate tours if you book as shore excursion from the pride of America due to their change of itinerary. Travelled with a local tour operator for both, cannot recommend this company enough, both tours had fantastic, enthusiastic, knowledgable drivers. Check in with them at the port was quick, clean air conditioned buses. Enjoyed both trips immensely and learnt lots about the island. I would definitely book with them again.
We enjoyed the Waimea Canyon trip but the River part of the trip was a disappointment.
The view of the canyon was nice, but the short boat ride to Fern grotto as a let down. No wild life to see and nothing other than trees lining the river.