huh.. completed it very easily, 3 ladders untouched, right side of the map left unexplored. can't tell if those are red herrings or if there's an intended solution involving them that I missed.
Hi, the extra ladders are so that if you "lose" some of them, you can usually still win.
Also, you can skip the 2 ladders pit in middle if you use right side. So sorts of an alternative solution there.