If it's important to keep people out of the quarentined castle for now than you should make the rock hills around steeper because I managed to get all the way too Geophery and Geophery by walking and jumping my way there. Plus in one spot farther up I managed to crouch jump over the wall to what I can only assume are the pallas doors. Sadly you have most doors unopenable. I also used the same techniques to get to Ironwill King. I found it awesome that he has a line of dialogue scripted even though he's probably not intended to be reached yet. Also please make the mine/cave deeper or at least add more ore deposits, or something..
there's like, 800 ways, to get to the king, Including one where you can almost walk right up to him from the front (its like a small staircase of rock faces)
so that one is probably intended.
The castle isn't intended, but its not important to actually keep people out of it, and I imagine as the Castle is fleshed out more in the future, that there won't even be a quarantine, unless the Quarantine relates to a certain something(s) else, in which case, You, the blacksmith, will have control over/a heavy... say, in when it can be accessed again. (as in quarantine lifted/fixed/etc)