The second route is known as the "Truck Route or Piste de Camions". It is used by the local truck drivers because goods trucks are not usually allowed into the National Park. It leaves the railway line several kms east of the "car" piste and joins the beach ca 50-60km south of Nouamghar. You can leave the beach at "Toolit" (check spelling) ca. 30 km later. The route is far sandier than the Car piste and in a 2WD is very very difficult. You save UM1,600 per person byavoiding the park fee, but a lot of this goes upo in extra fuel.
An alternative is to take the Car piste to within 30km of Nouamghar, (after the sand dunes and just where the sea comes into sight). If you look to the left there are tracks mounting the dunes, this is the other route to bypass Nouamghar and is possible in a 2WD, but pointless as the worst is now over.
The other drawback is that in case of breakdown there is far less traffic on the Truck Piste than on the Car piste.