If you don't want to expend a lot of energy, then do the fern grotto. The barge ride is smooth. Traveling along the river is pretty. Once we landed, a short walk will take you to a deck where you can look up the cliff to the ferns growing upside down. The grotto used to be open, but no longer. A short walk takes you back to the boat and a cheesy hula, music performance on the way back. Would not do this again. There are many other activities/sites I would recommend.
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