People do the Panamerican Highway on pushbikes and you don't need to have 4wd to do it provided you pick your weather conditions. There is also Ruta 40 which is the iconic Argentinian highway running along the eastern side of the Andes. That goes to 5000 metres - 16400 feet so the air gets a bit thin and cold and VERY windy

We didn't linger as we had to get down far enough to sleep for the night so we didn't end up with altitude sickness. As it was, it wasn't a very pleasant night waking up every few minutes gasping for breath - called Cheyne-Stokes Respiration.