Thanks for the feedback, all.
They're all valid points.
I guess I'm getting caught with the two sides of my Gemini brain. By nature, I'm more of a 'smell the roses' rider and what I want in SA is to get more in touch with the culture and the sites as opposed to traveling a distance for the sake of it. I'd like to see it all, but it's probably going to have to be broken up into several trips rather than one long one.
I already had the plan of flying to Colombia and I've seen reports of people falling in love with it and staying longer than expected. And then the next one and the next one and the next one...
I guess I was just trying to pack it all in with some sort of unconscious 'gotta get it all or I don't know when I'll be able to go back' type of thing, which is not the smartest route to take.
If I decide at some point that I can get a minimum of 4-6 months and possible stretch it longer, then I'll consider doing the whole thing. Otherwise, I'll just focus on a certain country or two.
Thanks for reminding me about common sense!