@Vinnie
Thanks for this post! I have a contribution for the list. I was working out the fastest way through the Once upon a Somewhere area for the Speedrun, so I first mapped out the area and analysed the mechanics.
The basic idea is that you start somewhere (x) on location or map 1.
You can move in any direction. At some point point you will cross over from map 1 to map 2.
Map 1 and map 2 are actually identical to each other, except you will notice that when you go back from map 2 to map 1, the entrance point you arrived at has disappeared.
From map 2 you can