Christof Teuscher submitted the route:
The Fremont National Recreation Trail is a 135 mile long-distance multi-use trail in south-central Oregon’s Fremont-Winema National Forest. There are twro main sections separated by about 13 miles of rural road and highway. The northern part begins on the summit of Yamsay Mountain (8,196 feet) and makes its way south over Hager Mountain and along Winter Rim to the Warner Mountains, where it ends at Vee Lake. The trail is a stunningly scenic undiscovered Oregon gem far off the beaten track. Both the Oregon Desert Trail (ODT) and the Oregon Timber Trail partly follow its route.
Official trail info: https://www.fs.usda.gov/recarea/fremont-winema/recarea/?recid=70808
Teuscher's announcement of his FKT attempt contains more information on the route:
Note that the FKT route includes both sections AND the connecting roads.
Saulius Eidukas, Brandon Williams, Scotty Strain and myself will be attempting the Fremont National Recreational Trail FKT on Saturday, May 29. We will be starting at the summit of Yamsay Mountain at 8am and will attempt to finish around noon on May 31. Tracking will be here; https://share.garmin.com/fremontfkt and here; https://share.garmin.com/fremontnrt We will begin the FKT on the summit of Yamsay as opposed to the Yamsay Mt TH, as the summit is the official start of the FNRT in all the literature.