South-central Chile ("la region de los lagos") and adjacent Argentina have some of the finest scenery I've seen anywhere on the planet, though it's not nearly as interesting culturally or gastronomically as Mexico. There are relatively few paved roads, however, and not even that many unpaved ones in the region.
Wow, thanks for the input. In regards to the roads in Chile, did you need a mountain bike, or was a touring bike sufficient? Also what was the security situation like? How far apart are most towns/ places to stay/eat? The same questions go for mexico as well. I don't think I am going to be camping on this tour.