>>56232125In the oldest prototype we've seen, all the routes started as giant ass roads, before almost all of them were turned into something else. Cycling road and routes 13-15 were barely changed, with cycling road turned into narrow cycling roads, and 13-15 only having the road tiles removed and obstacles added. As you can see if you look hard enough, Celadon cave being visible from town, indigo plateau, sevii islands (in a completely noninteractive form) and all the towns that have water access were planned very early. People think this version of indigo plateau was post-game though. Pokemon league was called the "League Dungeon" and was in the removed town in the center of the map.
More info here:
https://helixchamber.com/2019/07/22/proto-map-analysis/ 
