I think I might have found something. I've always found the woodcutting place slightly strange as there are never normally people there yet a certain times at night, some of the engines turn on. More interesting in this quest it would seem, is the possible find of a secret tunnel under the mountain, yes I said it. After careful observation, I can see that the tunnel has a left and right turning.Unfortunately there is a grating infront of it (which of course I have tried exploding). I don't know if, as with the aliens, it is weather/time/character specific. Anyway, I have attached a link to my snapmatic pic of it. I would encourage you to have a look for it yourself though.
I have seen this tunnel also. It definitely appears to come to a "T" junction at the end. Also looks like the bars have been bent, as if someone has been in there before.