If you want to section hike it, its entire North American part is covered by the Eastern Continental Trail (ECT), which some people (very few, as in a tiny fraction of all A.T. thruhikers) thruhike it in a single calendar year.

https://en.wikipedia.org/wiki/Eastern_Continental_Trail

I segment hike the eastern AT probably monthly and encounter a half dozen thru hikers a year.

It’s a very busy trail with relatively good infrastructure .