I don't know if mountains have, and where, always impervious to cliff jumping.
uhm..mountain cliffs are different from others. But i can't swar it, so i'll have to try it.
And..what's that stuff you posted?
A. Random question:
Have you noticed that the map generator failed a lot in this world? In my area i have 3 terrains with a fake edge (those areas with the edge of 1 tile over the terrain) and exploring the north while i was mapping, i found 2 more. Never saw so much fake borders terrains.
I'll ignore the cutted rivers-lakes-caves. That's a common error.