There are a few screenshots of Castle Black Dragon’s exterior up at Lost Sosaria. As I noted there:

This noble fortress has become the capital of New Sosaria, and is the home and seat of power of Andrea Morgan, the Queen of the Land.
…
And yes, the game you see before you is, in fact Neverwinter Nights, with Shadows of Undrentide and Hordes of the Underdark installed. Doesn’t look as much like NWN as you may have been expecting, O Reader?

🙂 WtFD