Start where the road turns to dirt at the end of setti fadma, past all the villages. Take the dirt road all the way back, about 20 km, until you summit the pass Tizi N'Tacheddirt. It's a long, gradual uphill on the road past very remote terrain and remote villages, until you reach the national park trail. Soon, it gets steep as you gain more and more altitude. variations summit and back, or summit and over, can be done. Be prepared to carry everything you need for the full run, not really any opportunity for water or resupply. Incredible place.

This stunning point to point trail is the highlight of Lewis Pass. It beautifully chains together 5 river valleys while keeping you far from civilization from the first mile to the last. The footing is generally very smooth and runnable, and the climbs are quite gradual, so the times here have the potential to be very quick. Either direction works, but the most common one seems to be North to South which is a bit net downhill, but the travel time probably does not differ by much.