I just completed Mckeesport, PA to DC on a Dragonflyer trike, while pulling a BOB trailer. It is much more difficult to do on 3 wheels because I always had 2 wheels off the beaten path. The beaten path is very narrow. With only 2 wheels you can stay within the path. There is absolutely no need for a trip coordinator. Two very useful web links would be:

http://www.atatrail.org/pdf/LinkingUp.pdf

http://groups.yahoo.com/group/coTowpath/

Check em out.