From Mendoza: take the southern access (route 40/7) to detour by route 7 (towards the border with Chile) to Uspallata (section 130km.). Then take route 149 north, toward Barreal / Calingasta (this section has a distance of 110 km. of which 35 km. they are of rubble in good condition). From San Juan: take Route 40 north to Talacasto. Turn left onto Route 436 until the intersection with the route 149 (this section is 71 km from San Juan). Turn to left towards Calingasta / Barreal (it is about 135 km. Barreal, all paved except for a section of 25 km., Which is in arrangement). IMPORTANT: in no way, coming from Mendoza or from San Juan, take route 153 from Media Agua (route 40) to route 149, that passes through Pedernal and Los Berros. It is totally impassable, although the GPS indicates otherwise