Even with a simple colour scheme, painting a castle is a lengthy process. It's very enjoyable though, perhaps because of the sheer scale of a project like this and the knowledge that there's going to be a sizable, undeniably tangible output at the end of all this.
Ordinarily I don't use metallic paint. Here though it makes sense to employ the old pot of Tin Bitz that lurks at the bottom of my paint case. As a metallic base for statues and the like it's perfect. The lighter grey is GW Celestra Grey and the darker, greenish grey is P3 Cryx Bane Highlight. Wood tones and weathering to follow.