@maxx Oh true, I didn't explain that, but is quite simple, you have to go to the 3 points in that order. The map in game will show you that points if you have the bones.

The Numbers Mason, What Do They Mean. Seriously, I cant figure out what the red 1 2 and 3 means on the guide.

Thank you, that's really interesting - I missed or didn't see the significance of two of the bone clues you've kindly listed.

@RobertJPaynter
1. Yes, the bad ending is obtained by dying in that part of the late game, I had read that there are limited moves before it kills you, but it seems to me that no, that you only get it if you go to the escape place (light blue) without doing the bone thing.
2. Right, there are clues for each of the bones, that's the most visible one, the others are inside the furnace in the hut, behind the poster in the radio tower and the book in the camp.

I'm glad it was helpful to someone.

Many thanks for your guide - it has been really helpful as I had just been going round in circles in the late game (I didn't understand the use of the compass before I read read your description of taking the final path). Just two queries out of curiosity: firstly, I spent the whole game fearing I was going to die by encountering the enemy (!), but from what you've written this is only possible in the late game - so can the bad ending & achievement only be obtained by entering the light blue area on your map? And secondly, as far as I can see, the arrows on the cave wall are just the route from there to one of the bone locations - is that right? Thank you again.