Before arriving at Port de Castet, park 50 m above the watering hole, taking care not to obstruct traffic.
(S/E) Take the track that climbs north of the watering hole for about 300 m, marked in yellow; you will then come to a gate that you should close behind you.
(1) Follow the track that descends slightly to the left, passes alongside a house, then continues uphill and turns into a well-marked yellow trail. You will come out into a fern forest with brambles (periodic burning in winter).
(2) Climb for about 100 metres to reach a fork.
(3) Continue straight ahead, climbing northwards through the fern forest. The path, still marked in yellow, soon enters a sparse forest with stunted trees growing among numerous rocks. It zigzags from rock to rock and arrives at the bottom of a long meadow with a few large beech trees.
(4) This meadow leads, via a well-marked path marked in yellow, to a small pass on the ridge. This path is steep and zigzags through this ungrazed meadow with tall grass, between a rocky area on the left and a forest on the right.
(5) Once at the pass, enjoy the view of the plain. Continue to the right on the unmarked rocky ridge (watch out for children) towards the Soum de Las Picarras weather vane, the highest point of the Rey ridge at 1,349 metres.
(6) Return to the car park (S/E) by following the same route you took on the way up. Please note: on the way down, be sure to follow the marked path you took on the way up. Do not descend through the forest (on the left as you go down) directly towards Port de Castet, which you can see between the trees, as dangerous rocky outcrops prevent you from doing so.