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.