No special access issues
Park your car to the Allee des Vaches (near the La Caverne des Brigands). The total approach is ~600 meters (less than 10 minutes).
Walk for 330 meters and take the left road and walk that for 150 meters. Turn left and you'll find yourself on sandy area. Walk forward and you'll find a path leading you to the sector. You'll get to Hieroglyphes after approx. 200 meters.