Any thought's about trekking 5.200 Km from Pasto to Tucuman?
there is very limited information about this trek, there is one book called "La gran ruta inca. El Qapaq Ñan / The Great Inca Route. The Qapaq Ñan. Second Edition" about a peruvian that trek 4.000 km of this road system.
you can find it here -> http://www.petroperu.com.pe/ediciones/EdicionesVarias.asp?num=20026
Also this book and documentary "Qhapaq Ñan" about a couple that trek 6.000 km.