The only thing Central America and South America have in common is the language, and even that is a Barely. Spending all your time in one country is like parking yourself in front of one entre at the smorgasboord. Go ahead and fill up on the tacos, but then you won't have any room for the ceviche or the parilla. The cost of shipping from Panama to Colombia is the same as shipping from the US to Colombia. If you want to spend a year riding Mexico, I really don't care. If you want to skip Central America, I really don't care. I mean, I don't begrudge you your version of adventure.