East Coast Overnighter, that is pretty much an oxymoron. That is not to say you couldn't do an overnight on a bunch of different runs, but in most cases there is little point. Runs that are possible to overnight on in the summer: New Gorge, WV; Hudson Gorge, NY; Alagash, ME; a ton up in Canada (Magpie comes to mind).
In general there just isn't enough undeveloped river front property over there to give you an experience comparable to a western overnighter.
"A river is more than an amenity, it is a treasure."
-Oliver Wendell Holmes writing for the majority in New Jersey v. New York