Go to the Old Washington Street Bridge between Hanover and Pembroke there are some lovely views of the river with no danger of getting your feet wet.
This is the point at which the river narrows and beyond which most day-trippers in powerboats turn back. At low tide you could wade across ankle deep, if you can keep your feet against the strong flow as the upper marshes empty through this point.
Whoops! There goes another one of those elusive Blue Heron again.