Access by car via Esparros to the Col de Oueil Lusent, where there is parking available.
(S/E) Head slightly downhill along the forest track towards the south-west for about 500 m, until you reach a left-hand bend with two cairns at the start of a path.
(1) Turn left and follow the path for 2 km through the forest, following the yellow markings which are somewhat spaced out. On leaving the forest, you will emerge onto the grassy slopes of Courtaou de Tire-Mouréou.
(2) Before the wide pass, look out for a large cairn on the left in the middle of the meadow, followed by two small posts with yellow markings: signPR®1thenPR®17. Head straight up to the left across the middle of the meadow, then cut diagonally to the right towards the rocks until you reach a solitary tree. Pass well above it: you may sometimes find yellow markings by climbing straight up the slope and following a sort of track (clearly carved out by water).
(3) Go round the Puits de la Pindorle on the left, climb up the gully aiming for the pass to the right of the Signal de Bassia whilst following the large, elevated rocks (with yellow markings) above the grassy area. Reach the Col de Bassia straddling the slopes of the Baronnies and Payolle.
(4) Follow the north-east ridge to the left to the Signal de Bassia.
(5) Continue a few metres further up to the second cairn: stunning panoramic view.
Follow the ridge eastwards: descend about 60 m to a pass via the pylon, then return to the ridge. From the pass, climb to Cap de Castillon.
(6) From the summit, you can see the Castillon hut in a green meadow, in front of a forest: there is no path leading to it. Follow the north-east-facing ridge down a steep descent to a sort of pass.
(7) Continue slightly uphill over the small mound: be careful not to veer off to the left. Then descend, keeping further to the left, to reach the grassy area at the Col du Castillon and its hut.
(8) Follow the path below on the right. Reach a large cairn in the forest.
(9) Turn right onto a path, passing through a gap in a ridge (climbing spot). Continue at a leisurely pace to reach the Col de Oueil Lusent car park (S/E).