Park in the car park on Avenue Charles de Gaulle in Saint-Laurent-du-Pont.
(S/E) Follow Avenue Charles de Gaulle towards the town centre. At the traffic lights, turn right onto Avenue Jean Jaurès and continue to Place Aristide Briand, recognisable by its fountain. Turn left onto a pedestrian alley, from which you can see the chapel atop a hill.
(1) At the sign for “Saint-Laurent-du-Pont”, follow the signs for Route de Fontmartin. Opposite, climb the steps and then follow the winding path leading up to the chapel.
(2) Leave the chapel on your left, then shortly afterwards take a path on the right which crosses a flat meadow. You’ll come out onto a road.
(3) At the “Route de Fontmartin” sign, head towards Le Mollard by keeping to the left on the forest track. Pass two hairpin bends and, 150 metres further on, you’ll reach a Fork in the road.
(4) At the “Le Mollard” sign, hidden behind some undergrowth at the corner of the fork, leave the road opposite leading towards La Grande Sure. Turn onto the track on the left towards Côte Vieille, where, after 10 m, you will see the sign on the right. Climb a steep, stony slope and reach a junction (alt. 760 m).
(5) At the “Côte Vieille” sign – the altitude of 700 m shown on it is incorrect – continue to the right towards Folatier. You will reach a fork in the path (elevation 852).
(6) At the “Folatier” sign, ignore the sign for “Sous le Rocher du Pin” on the right. Continue along the path to the left towards the Rocher du Pin. Climb up a steep slope via numerous seemingly endless hairpin bends. After a virtually level section, resume the climb until you reach a junction (alt. 1090 m).
(7) At the “Le Rocher du Pin” signpost, take the path straight ahead towards La Terrasse and Le Cul de Lampe. It climbs gradually and, after a wide bend to the left (alt. 1,300 m), leave the path continuing straight ahead to turn onto the steeply sloping path to the right. After 150 m, you’ll reach a junction with a path heading in the opposite direction to the left (alt. 1,340 m).
(8) At the ‘La Terrasse’ signpost, head straight on, following the sign for ‘Cul de Lampe’ along a gently ascending path. You’ll reach a cirque filled with a vast scree slope, which the path skirts along the top of. Cross a steep section through the rocks and reach a junction (alt. 1,400 m).
(9) At the “Le Cul de Lampe” sign, do not take the prohibited path leading in the opposite direction to the right. Stay on the path opposite, heading towards the Col de la Sure, and arrive at an unsigned junction where two marked paths emerge from the forest, offering a sweeping panoramic view (alt. 1,490 m).
(10) On the left, ignore the path leading to the Col des Charmilles. Continue straight ahead towards the Col de la Sure, clearly visible at the top of the valley (elevation 1,675 m).
(11) At the signpost, head right towards the Grande Sure. Climb a stony path and over a few rocky slabs. Descend to a small pass before resuming the ascent to the summit (elevation 1,920 m).
(12) Return to the Col de la Sure.
(11) At the pass, take the unmarked path (north-east) situated between the path to the Cul de Lampe and the one to the Col de la Grande Vache. Clearly visible, it crosses the grassy slope of the Mollard de la Grande Vache halfway up, almost level, to reach the foot of the Col de la Petite Vache (alt. 1,630 m).
(13) Continue straight ahead along the path. Cross a woodland, then return to the meadow and reach a crossroads in front of a fence (elevation 1,605 m).
(14) At the sign for “Col des Charmilles”, turn onto the path on the right towards La Salle à Manger. In the forest, start with a steep, winding descent which levels out as you walk through a small valley. Continue along a track, cross a stream and, 150 m further on, arrive at a junction (alt. 1,170 m).
(15) At the sign for “La Salle à Manger”, turn sharply left towards the Chartreuse de Currière via the Sentier des Agneaux. Cross the stream again straight away and immediately turn right, ignoring the path leading uphill opposite. The gently sloping path descends before climbing slightly up to the Col des Rochers des Agneaux after a section running alongside a rock face.
(16) Take care not to slip whilst descending the tight, stony hairpin bends on the steep slope of a rocky cirque. The slope gradually levels out until you reach the Route Forestière de la Charmette (alt. 870 m).
(17) Turn left onto this road and go through a barrier prohibiting vehicles. When you reach a car park, ignore the Chemin de None on the left. Walk past the remarkable Chartreuse de Currière and through the small Sourd tunnel. Continue along the road to join the D520b.
(18) Follow it straight ahead, keeping to the left-hand verge. Enter Saint-Laurent-du-Pont. At the traffic lights, cross Avenue Jean Jaurès and head for the car park (S/E).