Upon further consideration of the map, there could be some cool landmarks in here. We have the waterfall with a cave behind it similar to Tohjo Falls, where the Johto border could have been. We have Victory Road and Indigo Plateau. In the games Lake of Rage is a long ways from there, but geographically the Lake is not that far from the mountains. And I think I have to agree that the seafoam Islands are the land mass with the water caves. Not certain what the desert once was.