Le Grand Serre via La Grande Cuche

Park in the village of Le Sapey, located just past Lac Mort, the^first of the Laffrey lakes when coming from Grenoble.

(S/E) Follow the yellow-marked^{PR®® trail}. Stay on this trail, turning left at the junction leading to Les Bigeards. Continue uphill to reach the Col du Fond des Sciaux. Take a moment to consult the orientation table here.

(1) Continue left to quickly reach a crossroads of paths.

(2) Enter the forest via a forest track (not shown on the map) or by cutting through the forest heading south-southeast, passing the end of the hairpin bend on the road descending from the summit of the Grand Serre. Then climb back up through the forest, following the ridge as best you can: this section is unmarked and steep in places. Reach the bottom of a clearing.

(3) Climb up, veering slightly to the right, until you reach the change of slope. The section is short but very steep.
When the slope becomes more manageable, look for a few orange arrows to reach the Petite Cuche.

(4) From here, follow the orange dot markings, which generally follow the ridge line across grassy slopes that are unmarked and still steep, up to the Grande Cuche, a barely noticeable secondary summit.

(5) Continue straight ahead to find the yellow-marked path, follow it and reach the summit of the Grand Serre.

(6) Return to the previous junction by retracing your steps.

(5) Turn left and begin the descent via switchbacks. Reach the edge of the forest.

(7) Take the correct path on the right, cross the Bois du Champ du Fau, pass the Ru de la Combe de la Coirelle to reach the crossroads you passed on the way up.

(2) Turn left and follow the route back along the same path to return to the Sapey car park (S/E).

This description can be supplemented by this one.