(39.115673, -79.484276)
When you come into the park there is an intersection where you can go right, left, or forward. Forward takes you to the main viewing platform and the Trading Post. This viewing area is accessible with a wooden deck, stairs, and ramps leading down to the overlook. If you go left at the intersection, you will find the platform on the other side of the river, called Gentle Trail. People do get in the river here, though I'm not sure of the access, as I have not had the desire to do this, but Falls Run seems a likely suspect.
