My first excusion from Salta was to Cachi, and I opted to do this trip with a traditional turist agency. You know, a bus (minibus, though) and a guide that talks too much. And who plays too much music. Nevetheless, the day offered stunning views. Cachi is about 200 km from Salta and the highest point on the road is on 3340 metres above sea level. Cachi itself is a sweet place, but the road going there is what makes the trip worthwhile.
The climate in the Salta area is dry most part of the year, but summer brings lots of rain, at least in some places (others appear to be in more or less constaint rain shadow). I arrived there in end of September, that is in spring, so I saw many wide river beds with small tiny water streams.