Winter thru IMO means leaving Maine in say November and finishing in Georgia in march.
Anything short of that is not a winter thru IMO . As for 25 mile days in Georgia as I have read here, pretty much out of the question in winter, and virtually impossible in warm months. That's a tough stretch to consistently do 25's . This kid is attempting to do what thousands have done before him. The pursuit qualifies as not a winter hike nor even an unusual hike. Dozens will leave Maine after he does.