Any single trail transversing a mountain chain is bound to miss some great places. There have been many times that I have been on a hike and said to myself "wow, I wish the AT went through here!!"
Where would you put the AT? Complete disregard for logistics and the need for a linear trail is a must .
My top three:
Grandfather Mountain in NC, the ladders are a fright!
Allegheny National Forest, PA...the 'mountains' of my childhood.
Acadia NP, of course!!!!