Route: Mt Katahdin (ME)
Being the most direct access to Baxter Peak, the Abol Trail has the reputation to be steep and relentless. The Abol Trail was closed from spring 2014 to summer 2016 due to a rock slide that occurred in 2013. A new trail segment has been opened, which, before reaching the rock slide, will diverge to the northwest, making a traversing ascent before switchbacking along the rib that is west of the slide. The route is now slightly longer (3.6 instead of 3.2 miles), less steep (average 30% instead of 47% on the slide part), and slightly easier (less scrambling and firmer ground). However, the most challenging part, the upper slide, remains unchanged. The GPS track on this page includes both the new and the old trail.
As a result of the re-route, new FKTs will have to be set for the new trail. There is a Strava segment for the ascent.
Another route is the Helon Taylor Trail from the Roaring Brook CG over Pamola Peak. It is about 4.1 miles each way.
Still another way is the Hunt Trail from the Katahdin Stream parking lot, about 4.6 miles each way.
The Thoreau Traverse ascends the Hunt Trail from Katahdin Stream to the top & then down to Roaring Brook via the Helon Taylor Trail (or the other direction). It is logical to do this out & back, unless one has arranged a shuttle of some sort.