1
From the "Porte d'Herbouilly" (alt. 1280m), head northwest on the undergrowth path towards Saint-Martin-en-Vercors.
2
At the intersection, descend left towards Favier, following the yellow and red GRP markings. The path passes over small rocky slabs (care should be taken in wet weather), to reach the intersection of "Favier" (alt. 1211m). Follow the direction of Pas de St-Martin on the right.
3
At the next crossroads, do not continue towards the intersection of Chemin de la Pia, but follow the path opposite (yellow and green markings crossed out), to join a perpendicular path on the descent. Take it on the right, now following the yellow and green markings, to make the fairly steep climb towards Pas de St-Martin.
4
After climbing a few rocky sections, you will arrive at a ledge path that leads to the "Pas de St-Martin" (alt. 1305m). Beautiful panorama from this take-off area.
5
Continue along the ledge (be careful: cliffs on the left!), past a cabin. Then enjoy (with caution) a magnificent view of the Roche Rousse cliffs.
6
Continue along the path that leads into the beech forest. At the crossroads, turn left and soon reach the junction for "La Parcelle 5" (alt. 1350m). Then turn right to reach the crossroads for the "Tenailles" car park (alt. 1310m).
7
Cross the road and take the track opposite that leads to the "Herbouilly" crossroads (alt. 1290m). From there, follow the yellow and red GRP markings again, turning right to cross the Herbouilly plain (protected natural area) due south.
8
At the junction with the D221, at "Pot du Loup" (alt. 1300m), turn slightly left and follow the road. At the "Roches Rousses" post (alt. 1290m), leave the road and head right onto the track.
9
At the crossroads, take the route you initially took on the left to reach the Porte d'Herbouilly car park.
