James, that is truely sublime. It has such a simple feel to it, but, on close observation, it has a lot of detail. Take the stairs and the arch for decoration over the door way to a small corner tower as examples.
I really like the way your doing it in stages. I it can happen that, when a MOC is first started, you build things really detailed; but, as things progress, you're tempted to "hurry up and get it done", therefor sacrificing some would-be detail. However, your stages approach really fixes that problem.