The railroad network extends just south of Mexico.
Beyond there, you have a few two-lane roads as far south as the canal (with highways near cities).
There are currently two bridges across the canal with a third under construction.
There is NOTHING south of the general canal area.
The Darien Gap has, at MOST, a rough hiking trail or two. Not even jeeps can pass through into Colombia.
Of course, a railroad has been proposed as far as Panama, and in this scenario an extension through to South America is conceivable, but it would be rough.
Beyond there, you have a few two-lane roads as far south as the canal (with highways near cities).
There are currently two bridges across the canal with a third under construction.
There is NOTHING south of the general canal area.
The Darien Gap has, at MOST, a rough hiking trail or two. Not even jeeps can pass through into Colombia.
Of course, a railroad has been proposed as far as Panama, and in this scenario an extension through to South America is conceivable, but it would be rough.