Like Dragonborn's Solstheim is to Bloodmoon, it's not an exact copy. It's a "cover version", in the same way that Johnny Cash covered NIN's Hurt or Amii Stewart took on Eddie Floyd's Knock On Wood: a homage, not a facsimile. It should be recogniseable to those who played the original, but is very definitely its own animal.
This mod will require Dawnguard, since it uses the vampire castle tileset and other bits from that DLC. It will also, obviously, require Dragonborn.
The idea is that I will complete as much of the interior as possible before Dragonborn is released and then just plop it into the worldspace, so to speak. I have no experience of making large exteriors in Skyrim, so it will be a learning curve and I'll probably need help with that.
Here are some screenshots of what I've done so far:
http://s43.beta.photobucket.com/user/princess_stomper/library/Solstheim%20Castle%20-%20a%20cover%20version
The library is just a retitling of the "study", since I thought the word "study" more befitted the smaller study elsewhere in the building. The "chapel" is just the area at the end of the upper hall - it and the bedrooms are all one cell so you won't see the title in the game - and the "secret shrine" is part of the entrance hall cell. I've moved the servants' quarters to a new corridor/staircase so they're no longer reached through a trapdoor in the kitchen, but through a door next to the kitchen entrance.
I'm about 20% complete with the castle interior. I'll see how that goes before tackling the surrounding village. I have no intention of adding any sort of quests or ownership restrictions, though I may add in a note somewhere telling the player that you have inherited the castle from a relative. I'm currently trying to work as quickly as possible while I'm on this creative streak because finding the time and energy to mod lately is very challenging. This is why, until this mod is complete, I've halted work on my other endeavours. (I still intend to complete them, though.)
I did try through various means to contact Korana to tell her about it and ask for her "blessing", but have been unable to reach her. I can't imagine her having any sort of objection to the mod, so I just hope and assume she'd be OK with it.