I'm still in my blue period*, so here is my first draft of a castle/keep located next to a river/lake/ocean. The isolated towers are on their own little islands and they have access via the dungeon. I still need to add the various details to the rooms, castle/tower walls, land and water.
Click image for larger version. 

Name:	bluecastle001.jpg 
Views:	1237 
Size:	693.0 KB 
ID:	11190

* With apologies to Picasso.