Gect: after playing around I think it's easier to play with animation snapshots and adjust when the end frame is. The script you linked me to is good but unless I'm using it wrong I can't paint in a straight line...
I could use it for maybe the inhabitant's earlier attempts at building along a cliff and things are all wonky though...

twisted: thanks. I'd post images of references of my main inspiration but I can't find any decent ones...
I was thinking about what was at the bottom of the cliffs... At first I thought maybe there's nothing there... it's just rock, or spiky rocks. Then I wondered why would anyone want to live here if there's nothing but certain death at the bottom... perhaps the inhabitants are exiles, perhaps they like living next to danger, perhaps they are hiding from something or someone, or perhaps there are minerals to be mined..
I think that it'll be water down there. After all... why would you build a place to live if you can't get water?
So there's a river at the bottom of the cliff.