Unfocused Thoughts on Karse

Normally I do these posts for something I haven't developed as much as I have Karse, which I've posted about a few times, but I want to nail down some of the bigger picture stuff and think about how I would actually run it.

The name, I should note, comes from taking Sark and Gygaxifying it.  After hearing it said "Cars" by a number of blog readers I play online games with, I added the E to make it clear it rhymes with arse.  Apparently there is a place in the Forgotten Realms called that, but I haven't thought of a better name yet.

• Karse is made up of a set of islands - a largish main island shaped like southern Britain, smaller islands that are like a split off version of Wales and Cornwall, and an archipelago like the Heberdies stuck at the top.
• The main island is home to a fair number of towns and one city - the capital of Nindle.
• The area between these towns is sparsely populated moors and marsh or the occasional greenwood. 
• These between-spaces are the haunts of giants (leftovers from the first race to live on the islands), fairies and elves (the second race), the undead, and vicious bandits.
• In a crater lake north of Nindle there sits an island.  On that island are the ruins of Llamalot, the capital of Rutha the Unconquered who united the peoples of Karse long ago.  This acts as a large dungeon/ruincrawl for those who like that sort of game.
• Travel between towns is fraught even in the day time.  Visibility is rough due to the almost ever present mist which is only occasionally banished by the Sun, whose glare then blinds the Karslish eye unused to its presence. 
• The most famous giant roams the remains of the road between Nindle and the ruins of Llamalot.  His name is Headless Jack.  Once he had two heads, but Brutus, the son (or maybe father?) of Rutha took off one of the heads and now he roams the countryside mourning the loss of it.  If you hear his cries come from across the moors you'll get the shits.
• The idea, in case it was not clear before now, is to create a kind of spooky/miserable setting based on British folklore, folk songs, Arthurian Myth, Celtic Mythology, and filtering that through the World of Nightwick as already established.
• Other monsters include fomorians, linworms, nuckalavees, and any number of other British or Irish bugaboos.
• Social class would play a big part in town - where the gulf between the nobles and the peasantry is vast - but very little part in the misty wastes between them.
• Brian Froud and Alan Lee are major visual influences but you kinda have to imagine them with meth mouth.  The over all effect, I hope, will be something like a mix of Excalibur, Jabberwocky, and Hammer Horror.
• I'm not sure if I would use some version of D&D for this (either OSD&D or 5e) or some WFRP derivative, given the tone.