Border crossing in Assis-Brasil / Iñapari is no worries at all.
If you are coming from Brazil to Peru, after the border, you have a paved road to Puerto Maldonado and Cuzco (InterOceanic Highway - beautiful).
Let me know if you need any additional info.
Originally Posted by ElReyDelSofa
Kito, will be very interested to hear how this route works for you, especially the border crossing at Assis/Inapari into Peru. This is the route I have in my mind to follow when the univers aligns for a S. America trip for me.