8600 km, 5 months
Start by crossing over the Andes, by the famous 29 switchbacks up to Portillo, Chile, and down to Mendoza, Argentina. North through Argentina’s wine areas then back over the Andes and into Bolivia passing over the Salar de Uyuni salt flats. Visit the UNESCO World Heritage cities of Potosi and Sucre, then onto La Paz. Enjoy the effect of the strong south east trades through Peru to historic Lima. North though Ecuador visiting the cities of Cuenco and Quinto. Finally ending up in Colombia to partake in the coffee culture.
Two issues dominate the timing decision: the Andes passes need to be snow free and Bogota has a dry season mid-June to mid-September. The wind in Peru would suggest travelling from South to North. Starting in Santiago some time during Feb-Apr would be sensible, so as to arrive in Bogota in the dry season.