So deriving from that, I came up with this, however, It doesn't have the level of control I'm after. Does anyone have any other ideas that would allow the "zone" to be stretched further into the water if need be? This has a limit to just at the shore edge. It'd work better if I raised my water level but currently water is at -0.2 and based on flat ground.
Apply the terrain to the Main Input of the Shore shader.