Park in the car park of the Museum of Prehistory, located south of Vassieux-en-Vercors.
(S/E) Continue along the PR® path, marked in yellow, running parallel to the road. Reach the Espeline junction, a crossroads with several directions.
(1) Take the GRP® Tour du Vercors Drômois opposite. Heading due south, reach the Baraque Forestière and the Fontaine du Lauset.
(2) Stay on the GRP® trail, following the yellow and red markings, to reach the Baraque Forestière and the Fontaine du Plainet.
(3) Turn left then immediately right, passing in front of the Refuge de l'Entrecol. Continue the climb and reach the ridges.
(4) Leave the GRP®, take the ridge to the right and reach the Col de la Chau.
(5) Stay on the ridge to begin a steeper climb that ends at the summit of But Saint-Genix.
(6) Take the path on the right downhill and now alternate between the yellow-marked PR® and the parallel path that branches off the cliff to the right. Arrive at Pas Forent.
(7) Continue the descent on the path on the right, then follow the PR® to reach Pas Bouillanain.
(8) Turn right onto the PR® (yellow markings); further down, at a hairpin bend, you’ll come to a wide track in the Combe de Gaza.
(9) Turn right onto it and follow it until you reach the junction with the GR®93.
(10) Turn right, following the red and white markings, and, a few hundred metres further on, you will reach the junction you passed on the way out.
(1) Turn left and retrace your steps in the opposite direction to return to the car park of the Museum of Prehistory (S/E).