Park at Port de Castet.
(S/E) Start by following the road you came on, heading north-west. Ignore a path on the right that leads to private property.
(1) Immediately afterwards, leave the road by turning right (Route du Port). Go through the gate and at the end, turn left. At the next fork (altitude 950 m), continue straight ahead. Turn around for a superb view of the valley.
(2) Be careful to take the left: easy passage. On the right (no GPS track), the passage is very tricky for inexperienced hikers. After leaving the woods, climb steeply to reach an unnamed pass.
(3) Then turn right to climb up to Soum de las Picarras, which you can see from this spot. The ascent is along a ridge on a stony, unmarked path. From the summit, there is a superb 360° view.
(4) Return to the pass.
(3) Descend to the right via the steep north face. Turn left at the hairpin bend to join a wide forest path.
(5) Follow it to the right and join.
(6) Take a narrower path on the right that climbs back up to the Deus Coïgts Pass. The Tour du Rey path continues on the left, but I prefer this small path, which is well marked in yellow and red. At the next junction, keep to the right, continuing in the same direction.
(7) Arrival of the alternative descent from the summit (not shown on IGN but present on OSM). Col Deus Coïgts is not far away. Continue straight ahead.
(8) Cabin and arrival on the Deus Coïgts plateau (altitude 1,020 m). Descend gently towards the south. The markings disappear, but by following the wide path that crosses the plateau, you will easily find them again at the entrance to the forest.
(9) Keep to the right and continue downhill.
(10) Turn right onto the path, which follows the contour line and is therefore relatively flat.
An alternative is to follow a narrow path above the La Pomme stream, which winds its way through the ferns. This will take you to (S/E).