I've gotten most of the first post with equivs in gimp.

I get stuck with your

14. Select - Color Range = black with a fuzziness of 200. Hit the delete key two times then deselect.
Even using the provided sample, I can't get select by colour to get the area to align with the original mountain. I have some success by going back to a feathered version of the original lines, then selecting by colour from there...

??

-Rob A>