automatic polyline??

hello. I'm reasonably experienced with grasshopper as long as everything I do in gh can be done in rhino.... So i guess i'm still a beginner. But right now I'm stuck onto a problem which I cannot even guess where to start.... 

so here's a mesh that I wanna climb down following its edges.

and of course I have different ways to climb down: route 1 

route 2: 

etc. etc.

I want a script that can automatically generate these downward routes while analyzing each segment's slope. If a segment's slope is too high, I want it to stop and go for another one. 

I'm not sure even if this is the right idea cause the number of possibilities is astronomical, but is there any way to do this, or any precedent? 

thanks in advance...