There seem to be two types of folks who go to SA. The drivers and the travelers. The drivers go every day and many have to goal of getting to Ushiawa(SP?} Argentina as quickly as possible. The travelers seem to be generally European and Austalia who can spend 6 months in one country alone and then go back the next year and do it again. For information look Rick and Kathy with the traveling torguga website, Life Remotely and Trek of the Americas are other good ones.
We spent some time in Colombia this winter and it just didn't work well for us. You can read about our travels at patbickeljones.blogspot.com.