Submitted by Remco Wietsma:
The route starts at the Marketplace of Winterberg near the Hauptstrasse 1. Following the X13 you will reach the summit of Kahler Asten. It's the most iconic of the Hochsauerland summits at 841 meters high. Here you will find the first Winterberger Hochtour (WHT) signs that you will follow north. Winterberg lies in the center of the route, which follows the highest rigdes surrounding the town. After 82 kilometers you will reach the Kahler Asten again, after which it will be another 5k of backtracking the X13 back to the marketsquare of Winterberg to complete your FKT run.
Some info: I suggest to bring a GPS with the route on it, as there are a few places that have a double route, where you could take either one or the other road. Mostly these strechtes are only a few hundred meters, but this will prevent time wasted on navigation.
Map: Winterberg 655 Publicpress along with route research on https://www.wanderkompass.de/Deutschland/Winterberger-Hochtour.html