Car park near the farm of Chesnay.
(S) From the car park, follow the GR (south-west) for about 400 m.
(1) The GR heads diagonally to the right, then go left at the next junction and down the hill (several very large beech trees near a disused quarry).
A path leads off on the right: continue descending left to the junction.
(2) The GR continues on the left but take the PR (yellow) to the right, which leads to the hillside as far as (3) where we must cross a fence (at the crossing point). Beautiful oak dead ahead just outside. The PR heads down (line, westwards) along a small embankment and heads diagonally to the north (obvious). The track becomes a path and, after an isolated house on the hillside, reach the "village" (rather a hamlet) of Amenucourt via a small road.
(4) When this small road meets the one leading uphill to Amenucourt, head down (left) towards the village.
(5) At the junction with the D37, take the path to the left (south) up through field (reaches a place where you can park near the arboretum).
(6) Shortly after the car park and the fence, the PR turns right through the woods. Follow it until it reaches the hillside, then follow the line of the hillside ignoring paths from the left.
(7) Reach an area between woods and fields and continue to PR D100 (cross).
(8) Take the D100 to the right for about 500 m; enjoy a beautiful view of the Seine and La Roche-Guyon.
(9) The PR turns right headed due north and runs down the middle of the field.
(10) It leads onto a side road that you take to the left and remains roughly level for 1 km.
(11) Before the D313, the PR goes up the hill to the D100, crosses directly in front to take a small road in the cliff (here we join the GR2 descending to La Roche). Go to the castle.
(12) At the Château, the GR turns left along it, then turns right towards the church, and soon left again. It rises above the village, alongside it, and crosses a small road. Cross it, the GR continues opposite. Follow the (very obvious) path to several points of view of the Seine and the village. Several ascents and descents.
After a steeper descent, the GR goes back to the D100. Go onto the D100 (a few metres before the road, leave the GR that heads on a plateau to the right).
(13) Take the D100 to the left to the edge of the forest.
There, turn right onto the road along the edge of the forest (returning to a PR) and the next fork (marker 110), take the path on the right (it temporarily leaves the PR). After a flat few hundred metres the path descends steeply to a valley. Almost down by the gate, continue straight, cross the valley and start to go back uphill (marker 85).
(14) Follow the GR left and take the first road to the right that goes back on the plateau and leads directly to the car park.