Park in the Muandes de Bourlinche car park.
(S/E) Take the Pépinières trail opposite the car park, indicated by a sign. Begin a steep climb on this winding trail through the woods. Join a track and continue on the Pépinières trail. You will soon reach a crossroads.
(1) Take the right-hand path, make a large bend before rejoining the Sentier Widman. Take it to the left and continue along this path to reach the Chapelle des Séyères.
(2) Continue straight ahead, quickly reaching a fork, then turn right, still on the Sentier Widman. You will reach a hairpin bend marked by a cairn.
(3) Turn left and continue along three large hairpin bends to reach the summit of Mont Guillaume and its chapel.
(4) Take the path opposite and follow the ridge.
(5) Reach Mont Guillaume, then the summit of this ridge.
(6) Then begin the descent and quickly reach the Col de Trempa-Latz.
(7) Turn right onto the path that descends into the valley, then follow the Torrent de Sainte-Marthe to Séyères.
(2) At Séyères, follow the route taken on the way up to return to the initial crossroads passed on the way there.
(1) Leave the route you have already taken and take the path on the right, cross the Torrent de Sainte-Marthe ford, and continue along this path, keeping to the left at the next crossroads. You will come to a forest track.
(8) Turn left onto this track to return to the Muandes de Bourlinche car park (S/E).