We could have the ceilings illustrated to tell different stories of our favourite tales! Oooo and lovely plush rugs to line the halls and make everything super cozy. There could be dome shaped rooms that are connected by archways and all the walls could be lined with books. Each room being separated by a different subject(s).
It’s really lovely seeing everyone’s different ideas for what we can do!
I’m envisioning a reading room in one of the lower towers similar to the one in the British Museum 
At least a few labs underground as well… I’m definitely going to need a lab.
I really like that second picture Rimor posted with the library “hall”. I could definitely see that one in a castle.
But yes, the cluster of various styles definitely makes sense.
I fully support the eclectic interior designs! I’m sort of picturing a Hogwarts-like situation where there seem to be far more rooms than what looks possible from the outside, with some of the more obscure ones possibly changing position…? There’s a decent chance of getting lost in the corridors but at least you’re guaranteed to stumble upon some cool rooms!
Wander the halls as much as you like, the doors know where you should be.
Wander the halls as much as you can, for they have plenty for you to see.
Wander the halls as much as you wish, and you’ll soon bump into me.
Wander the halls for the whole of your life, and always you shall be free.
So many rooms but omg the spells!
Picture if you will…
You fancy a snack, but your current book is adictive, so reading as you walk you meander to the nearest kitchen. You walk into a kitchen, there is a breif flicker across the page and the weight in your hands vanishes.
You turn confused and see the book that you’re reading, that still appears to be open in your hand, is sat on a shelf just outside the kitchen door. You take a step towards the shelf and as you cross the threshold the weight returns to your hand and the book is no longer on the shelf.
You go back into the kitchen and spectral version of your book reappears, the pages still turn, it feels slolid it just has no weight, so you carry on reading as you hunt a snack.
A week or so later you’re trying a cake recipie from an ancient cook book.
You spoon out the mixture and fumble the spoon, you watch in horror as it falls towards the book, you grab the book out of the way just in time then drop it screaming becasue you have cake mix covered fingers and the book lands in the mixing bowl, still half full of cake batter!
At this point you walk away and clean your hands, theres no point making this worse. You fish the book out of the mix and you’re surprised to see the cake mix, slide off/through the book, the text as clear as when you first found it.
Your spectral book just survived a close encounter with cake, spectral… yes you turn and see the acutal book on that magical shelf just outside the kitchen door. All safe and sound and definatly not covered in cake. Thank Gods!
Note: Do NOT rely on this spell when returning to home, books and cakes do not agree with each other, especially old books!
Note 2nd: This spell appears to have been applied to any room where a book may be damaged by the activities occuring in the room. Labs, Kitchens, Bathrooms etc
Note 3rd: The castle knows! One room was changed from a mundane writting room to a lab, as soon as lab kit was brought in, a bookshelf appeared at the door and no physical book could be taken in.
Note 4th: This works on scrolls and papers too, the spectral versions act the same as their physical ones, but have no weight.
Note 5th: I took some blank paper into the kitchen to draw up some plans over a cuppa. Everything I drew on the spectral blank paper was transcribed to the physical papers on the shelf.
The castle knows!
"Have you seen the library?
Sure it has an indexing system. Every book has it’s own index card, ordered alphabetically and grouped by subject all nice and neat, but have you seen the shelves themselves? Chaos!
Books seem to be placed wherever a gap could be found, and while there’s evidence that it used to be organised that is no longer the case. It seems every shelf has fallen prey to “the wrong disc in the box” syndrome.
And yet… every time I’ve needed a book the index system is always correct.
I found a cookbook for muffins sandwiched between “The Lexicon of Liturgy” and “The Big Boys Bumper Book Of Baleful Beasties”.
I remembered its location, and once read I returned it to the shelves, but this time I placed it between “The Muffin Man Diaries” and “Basil of Baker Street, 2029”.
I returned to the index system and searched for the cookbook’s card. The location was correct, the location had changed.
The castle knows."
It may be a fire hazard but the majority of the rooms totally need to have a cozy fireplace in them somewhere – need to warm up the drafty castle halls somehow, and itd be perfect for reading!
The castle seems totaly fine with snuggling by the fires with a book.
Also fine with having a cuppa tea on your desk next to the book(spillage risk)** and with reading on the ramparts(risk of rain)…
**unless the desk is in one of the kitchens or labs
Fun fact: An occupied castle is usually warm.
The stone doesn’t transfer heat well, so while it may take a long time to warm them up, once the heat is in the walls they retain it for a decent time.
A cosy, occupied castle could douse every fire when people went to bed and it would still be warm come dawn.
As a fair few of us would be up at all hours of the night, with lovely little fires just crackling away, it would be quite easy to maintain a very cosy atmosphere.
When it comes to fire hazards, you only need to worry if you’re reading, wrapped up in a blanket, on the actual hearth itself. 
Side tables; spindly or sturdy, intricate designs or plain, each a characteristic version of every member of Thornmouth past and present. Oh and they should have matching/paired seating; huge wing backs, comfortable sofas, beanbags etc…
@TheMadHare, did you ever find a spell to make those dust golems? They’d be pretty nifty in the now very large domain.
@Strix, I may have found something for the dust golem situation. Although I imagine the moral quandary behind gifting inanimate objects magiqally crafted life could put a damper on my current project. I would like to call the spell ‘Life Breathing’ though, as I’m sure the act itself would seem quite self-explanatory once seen in practice. More details will follow if any kind fellow magiq users are keen towards the idea of having dust golems do most of the caretaking. Might be slightly off putting to have black air-like beings floating amongst the shelves and passages of the library.
Speaking of the library, here are a couple images I’ve set aside for just this situation:
I would be interested in seeing these dust consuming golems, but I have just one request regarding their form.
Can they please be rabbits?
Can we have Dust Bunnies?
Undust Bunnies. So Wonderland. 
I’m obsessed with all of these. Was definitely a Thornmouth in another life 
I’m totally onboard for dust-bunny cleaners 
and that castle @TheMadHare posted is pretty awesome, and I really like the idea of organic burrow-like structures under the castle.
We’re really pulling this thing together guys 
There are really cool! I can definitely see them in the older parts of the castle/layered architecture mashup.
Undust Bunnies. Very good name. Agh the imagery is too good! Imagine pulling out a dusty book and whoosh! Suddenly a immaterial rabbit runs past/through the shelf, gathering the dust into its body as it goes!
Ah, I always knew I would have dusty spectral bunny children!
I also realized partway through my posting that those structures may seem quite Balimoran, given how consumed by flora they are. Then again, I would love to see some Undust Bunnies running through those organic passageways. Are there rules when it comes to this whole guild-hall-appearance dealio?
(EDIT: For anyone interested in the castle itself that the grassy “Well of Initiation” is from, it’s a place in Portugal called ‘Quinta da Regaleira’ and it’s actual construction is amazing. I advise looking into it!)
