At best you can have Bolivia, Chile, Argentina, Uruguay, Paraguay and Southern Brazil(Argentina not loosing it) as one country and then Gran Colombia and Peru as another country.
Why this ones?
For the first communication isn't so difficult, maybe with the exception of going to Chile. The only we need is a reason for this country to stay together, like avoiding the stupid things Buenos Aires did. What I think is having an organized Revolution in 1810 in all the big cities, which can avoid Buenos Aires considering itself the heart of the Revolution. Then when war comes with Brazil, we have to avoid stupid peace deals and that should make the trick to keep half Rio Grande do Sul, and the rest of the Misiones.
For the second the difficult part is Peru, which maybe can stay with the rest of the country for fear of reinvasion. The rest of the country has somehow to avoid tensions, maybe also for the fear to the Spanish.