If you've got an endless road, with no cars, no animals, no life at all, why not go to 200 k/h.
OK, so we weren't the most responsible guys on Earth. But we just had to do it.
This is probably a "do you see anything?" tip. This is the road. Nothing else but the road. For miles and miles. This is the pampa. Bring water, put gas on your car, and drive along.
In the argentinian province of Chubut, where Esquel is, and more south, gasoline is much cheaper, since the goverment pays some percentage (otherwise it would be too expensive). So if you're travelling from another region, and have enough gas to get to Chubut, wait up and fill it up there. You'll save a lot.