[Edi]

If you fire up the map file in the editor, you need to click on the provinces in question. If you open the map file in a text editor, you need to find the command #terrain <province nbr> <terrain mask> and add 512 to the mask.

But just wait 5 minutes and I'll post a fixed Cradle map here. I just went through it and the damn thing had crapton of provinces that should have been #nostart but weren't and I also changed some mountains to border mountains so that some parts of the map are now only difficult to traverse instead of being impenetrable.

Edi