I'm trying to figure out how busy the AT will be in early October in western Maine?
We're looking to do a 6 day section and I'm trying to determine whether we need to carry a tent, or if we can plan on shelter space.
Early October should not be overly busy. South bounders (SOBO) starts around July and will be out of Main by that time. North bounders (NOBO) must finish before October 15 and many of them will already have completed the trail.
For SOBOs, June-July is the peak season for Maine. There are less than 500 thru hikers per season in this direction.
For NOBOs, July-August is the peak season (in my humble opinion). There is roughly 3000 thru hikers in this direction and about 600 make it up to Main/Katahdin.
This makes up the majority of the hikers (GA-ME, ME-GA). Section hikers and flip-floppers may still be in those areas. However those groups don't typically form a bubble.
There could still be large organized groups (such as boy scouts) taking 1-2 shelters. Although this is not proper trail etiquette (large groups should have their own accommodation) this can sometimes happen on the AT.
I would consider carrying a shelter anyway. October is starting to be cold and I personally find lean-to's not particularly warm.
GA>ME: Georgia to Maine
ME>GA: Maine to Georgia