I never heard of this route before. Sounds like a "new route" actually as far as FKTs go.

"A New Hampshire thru-hiking route
This route traces a contiguous path from the border of Massachusetts to the northern tip of New Hampshire and the headwaters of the Connecticut River. (New Hampshire's state motto is Live Free or Die, hence the name.)
Not a new idea in the least, a number of hikers through the years have pieced together S-N (or N-S) routes through New Hampshire. As far as I know, nobody has attempted to do this quickly in one contiguous push, or justify a particular route.
I have chosen this particular route, which is described below because it is straightforward, uses iconic New Hampshire trails and travels over some of the major highlights of hiking in New Hampshire without adding tons of extra miles, road walks bushwhacking, seasonal trails and confusing directions. It also passes a few optimal resupply points."

https://fastestknowntime.com/route/l...r-die-route-nh