Everything in this post has been added to the Illustration Gallery and the Map Gallery.
Firstly we got here a cozy little cottage, and a key that I quite like.
Cozy cozy cottage. 
A big ol’ key.
This is the Briarfolk Settlement:
The hill tribes and meadow clans called them the Briarfolk and thought of them as (and fashioned wooden icons of them as) a hairy and bearded people that could speak with sea birds and woodland creatures. They worshiped at strange standing stones or communed with their mysterious horned goddesses by leaping over bonfires atop hillocks beneath the gibbous or crescent moon.
This map is of a ruined complex left behind by these people, partially built into a cave system on a precipitous near-inaccessible island. Now the island is home only to black-beaked oyster catchers, sea-spry puffins, and the occasional seal colony – or so the locals say, though the keen observer will notice that they never draw too near it on their fishing vessels.
Half structure, half cavern, all ruin. 
Dramatic cliffs are the key to any abandoned island ruin.
Woof! That was a lot.
