Parking: Place Gilles Léontin in Boulbon.
(S/E) From the car park, turn left onto Rue de l'Église, then Rue de l'Hôtel de Ville, which branches off to the left. When you reach Rue de l'Enclos, turn right, then immediately left onto Rue de la Clastre.
(1) Turn right onto Chemin de la Montagne, then very quickly right onto Chemin du Prieuré, which climbs to the right towards the church and cemetery.
Go around the cemetery on the right, go through a gate and follow a path that climbs up to the right towards Moulin Bonnet.
This path was probably marked in yellow at one point, but there are hardly any trees or markings left. Continue along this path, take a sharp right turn, leave the path that branches off to the left and continue uphill on the track for about 200 metres.
(2) At the crossroads, turn right to visit Moulin Bonnet, which offers a beautiful view of the village of Boulbon.
(3) Go around the mill and retrace your steps to return to the crossroads you left earlier.
(2) Then go straight ahead on this main track to continue climbing up the ridge of the Montagnette. Ignore all the paths branching off to the right or left and stay on the main path. At one point, there will be more yellow markings. Continue until you reach a crossroads with several tracks. A small artificial reservoir on the left will serve as a landmark.
(4) Do not take the path on the left that leads to the Abbaye Saint-Michel-de-Frigolet (you can make a return trip to see it, but the markings are not good and there are many trails).
Do not take the path opposite, nor the one that branches off slightly to the right, but the one that branches off sharply to the right, marked by a cairn. It descends into the valley and is well marked in yellow until you reach the village. Descend this valley without worrying about the other paths.
(5) When you reach a bridge, take the path on the left that goes around the castle. Then take Rue Gaston Raousset opposite and then Rue du Barri, which turns right and takes you back to the car park where you started (S/E).
. Note that it took me 1.5 hours walking alone, without any real breaks (except to drink and look around), and the beginning of the trail has no shade, so in summer it's best to do it early in the morning or late in the day. The wooded section comes at point 4, when you descend towards the village (amidst wonderful smells).