I find the greatest value with my adjustable poles is going downhill. It really takes a lot of pounding off the feet. I adjust them long. I also have spring loaded poles that further absorb down hill load, the trade of is the spring take awhile getting used to them. The trick is shifting the grip to "palming" the top of the pole when in the steep stuff.
You can always slow down if the Trail is steep and the footbed difficult.
But God help you if you are hiking anywhere during the height of the black fly, horsefly or mosquito season, as that can be beyond tough— especially when without a headset and big dope.
I am thinking western MA can be as bad as ME. It sucks (literally) everywhere if you time things poorly.
I made the mistake of doing the waterfall steps the first time I went on the AT and almost decided to head back down to my car before I even got to the top. That first day I barely made it to Black Mtn Shelter by sundown and I swear I thought I was gonna have a heart attack on the side of Frosty Mtn.
A few years later I did Blood Mtn in the pouring rain and had a blast so I think experience is huge in determining the difficulty of a section.
"I am learning nothing in this trivial world of [humans]. I must break away and get out into the mountains to learn the news." --John Muir
Southern Maine. It's the Star Trek holodeck with the safety protocols turned off. Nothing comes close.
As for your list:
Mount Madison. - A pile of rocks,well prepared in PA for this, not hard at all.
Mount Katahdin. - A celebration difficulty is not noticed.
Mount Washington. - Via the Crawford Path, one of the nicest trails in the whites.
Mahoosuc Notch. - Yes, hard but also very fun, something to look forward to, but also it's difficult.
Cheoah Bald., Who? Actually I lost a friend to Nora there, but otherwise unremarkable in terms of difficulty.
Lehigh Gap / Superfund Trailhead. - Fun Fun --- (short) till I went on and there was no water for the next 18 miles or so.
The Priest. - I went SoBo here due to slackpacking. Yes it's a climb, but the fascinating part is the shelter log where people confess their AT sins.