THW - They are almost all pencil on paper. Sometimes I'll do them in pen but only if that is the end result. If I'm going to color them I use pencil.
Um, well, I guess after I finish the color version of the caldera I could try to throw together a bit of explanation. I don't follow any rigid process.
Though I do tend to do some similar things when coloring pencil works.
I'm doing the color right now and I think I'll be done by tonight. So possibly tomorrow when I put it up I can get to that.

As a side note, you and chick both think that the mountains should be much more rugged.
Can you link to a map that does this in a way you think is rugged enough?
And again, thanks for the feedback.