Ben Nephew posted the route with a little FKT history:
The Mahoosuc Traverse is a rugged 31 mile section of the Appalachian Trail from Grafton Notch in Maine to Gorham,NH. The trail is remote, includes almost 11k of climb, and is almost all technical singletrack. The Mahoosuc notch is known as the hardest single mile of the AT. The FKT route, as established in the early 1900's, stays on the Mahoosuc trail to Hogan road in Gorham and then continues for a mile on dirt roads to the parking area on route 16. The historical route was 29 miles due to a more direct trail up Old Speck mountain in Grafton Notch.
In 1927, Bob Monahan completed the route in 10:27.
That time stood until August 28, 1958, when Chris Goetze ran 8:06:30.
On September 7th, 2014, Ryan Welts and I ran 7:45:17.
A full report can be found:
I'll be giving this route a shot on Saturday (7/18/20) to establish a NoBo FKT, almost definitely several hours slower than the fine gentlemen listed above.