RealLifeLore presents “Why a Single Little Spot Makes Driving Across ‘America’ Impossible”
That strip is the Darien Gap in Panama, the last 60 miles to the Colombian border, although a Toyota Corolla is said to be able to 4-wheel bushwhack it.
The jungle is rugged and dense and there are sacred lands for indigenous peoples.
Otherwise the stretch would be part of the Pan-American Highway.
The idea of a Pan American highway occurs in Clive Barker’s novel “Imajica” as “The Lenten Way” connecting dominions (with gaps).