i need help finding the cabin in the mission after u find the plane.plz help! and i also need help finding the plane on the skull shaped island.

on the conture map where the search circle should be, there is drop shaped conture <top left of circle> , a big ridge i fink. any way the best way to describe it is 2 get to the top of the ridge then head south down the hill till u get to a lot of rocks and crap on the ground or till u get to where the hill goes up agin and turn right <east> at the bottom in a hole there is tiny dump of a shack.