Actually, a route from Goldenrod to Cianwood is a strong possibility. Look here. You can draw a straight line from Goldenrod City to the Whirl Islands.
And I assure you, this map is not a forgery.
Also, I found something interesting in the tileset used for caves:
Tracks, and what looks like a mine cart. There also seems to be a block, which I don't believe appears in the game either.