About half of this drive was on a dirt road! (we nearly gave up and turned round). The road itself wasn't too bad, it was all the dust created by every car that passed, and some roadworks.
The scenery was spectacular. We stopped at a few places along the way, including a water fall:
We had a picnic lunch sitting down by a nice lake.
On the way back we took a slightly different route - although still about 40 miles of dirt road, it was much better as we seemed to be the only car on this spectacular route and hence a lot less dust clouds. The scenery was different - going over mountains, and just as spectacular. The picture below shows where we had just driven from:
The whole trip took us about 9 hours with a few stop along the way.
There were a few police check points along the way, where we had to show documents. Not sure if this was because it was so close to the boarder with Chile.