[Skybird]

Closer to Iverstatt? There is a mod that adds a castle on the northern shore of the lake thnat is east of Iverstatt. "Riftborg" is the name, I think. There is also an older version of the mod named "mountain castle" or somethign with mountain in it - this one you do not want, it is old. It lacks originality, but is anything but small. Has its own guards and servants.

However, many homes have issues with spouses and followers entering them and living there, it's written to be another internal bug of Skyrim.

And another bug is that some places have immense clipping issues, and/or do not display the walls properly when approaching. Reason unknown. Solution: Save and leave the game, then restart it with that save game, and all will be visible. You can also try to load the saved game just wiothout leaving the gamed. Or you do a quick travel to some place and then immediately back to the original place you came from.