To get there by car, take the D902 towards Bessans – Bonneval-sur-Arc. About 1 km after Bessans, turn left into the Villaron car park (mandatory stop). Note that there is a picnic area with toilets.
(S/E) Cross the small bridge over the Arc and continue along the tarmac section to the Chapelle Saint-Bernard. Take the path on the right. You’ll stay on this path alongside the river for the entire route. You’ll reach the Rocher du Château and its archaeological site, where you can stop to look at the cave paintings, which are unfortunately difficult to make out.
(1) Continue to a small wooden footbridge and carry on over the flat rocks, some sections of which are covered with planks. Follow the path which passes between a few dry-stone huts; note the flat-stone roofs typical of the region as you go. You’ll reach the oratory at the entrance to Bonneval-sur-Arc.
(2) Turn back and follow the same route in the opposite direction to return to the car park (S/E).