Calendar Year AT hike

[T.S.Kobzol]

You're no fun ;-) You make way too much sense. :-)

If I were to spend a whole year hiking, I'd want to bounce around various trails to take advantage of pleasant weather.

Spending a whole year on the AT as the OP proposes is a bit crazy.

But hypothetically,

Many thru hikes last 6 months, so for a YOYO one could imagine the return trip taking at least that long.

You'd want to finish no later then the end of August so you can beat any bad weather heading back south. Working backwards, you'd leave Springer on March 1st, arrive at Katahdin August 31st. Return back at Springer March 1st the following year.

[T.S.Kobzol]

I would probably just walk the AT as designed, NOBO, because the odds of finishing this are already against me, but upon reaching Katahdin I would take a 'side hike' on the IAT to go as far as I could, weather permitting and if the weather says no more then I would fly back to Springer and go south with the hopes of reaching and completing the Florida Trail.