Northern Argentina: the quebrada, salt flats, and Cafayate
The classic paved loop through Salta and Jujuy, the altitude of Salinas Grandes, and the gravel stretches to check separately.
General travel guide. It does not describe rental terms.
The classic loop
The best-known northwest trip links Salta, the Quebrada de las Conchas to Cafayate, the Quebrada de Humahuaca, Purmamarca, and Salinas Grandes. The Quebrada de Humahuaca is on Route 9. Cafayate is reached from Salta on Route 68, about 183 km of pavement through the gorge.
Purmamarca sits under the Hill of Seven Colors. From there, the Lipán grade (Route 52) climbs toward Salinas Grandes and is paved.
Altitude and the rainy season
Salinas Grandes sit above 3,400 meters. There is no overnight stay on the salt flat itself: the usual bases are Purmamarca or Susques. The altitude is real, so many people sleep lower and go up for the day.
The usual season is April to November, including a dry winter. December to March is the northwest rainy season and several roads get difficult.
Gravel in the valleys
The classic loop on routes 9, 68, and 52 is pavement. The interior of the Calchaquí Valleys is different: Route 40 and provincial route 33 toward Cachi, Molinos, and Angastaco, including the Cuesta del Obispo, have a lot of gravel. So does the Quebrada de las Flechas, between Angastaco and San Carlos.
Anyone heading into that interior needs to check the road and whether the vehicle they are driving is suited to it. This note does not describe any rental company's rules.