I've been looking - unsuccessfully - for a forum on the Atlantic Coast Route. Haven't found one yet (thus "unsuccessfully"). Are there forums for individual routes?
We do not have forums specific to individual routes. If you have a question about the Atlantic Coast route, you could try searching some element of the question, or posting a question in the Routes area (http://forums.adventurecycling.org/index.php?board=2.0)
Also, are you aware of this Atlantic Coast description page? It has a fair amount of information available, be sure to read all of the tabs as well. You might find your answer there.
I hope this helps.