No. It's not strenuous.
You dont need to hike to go and see the falls, in fact you can be on a wheel chair but youre view is from above. But if you want to swim or come near the bottom of the falls, its definitely a climb down. This is still a must see place
I think it depends on the person, I talked with a few elderly people looked to be mid 60s to early 70s. The park has several look outs to see the falls and plenty of room to turn around if needed.
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