Thanks for all the advice everyone. I've gone through and tried various bits. Love the Pics of Italy, kinda funny that people are recommending such photos and ideas seeing as I am currently in Italy, Regione Veneto. Salve.

So I tried painting in the shadows and did a small mock up of the castle. When zoomed out in relation to everything else I think this turned out ok, not great but ok. The big problem as I see it is there is no color harmony leaving it flat. It did manage to portray depth. All in all I think this is going to be the road I'm going to take but I think instead of trying to make this an exact clean edge map I'm going to shift towards more of a painting. Well see how this works out. The green is transparent, forgot to add a color to the background transparency layer.
Click image for larger version. 

Name:	Cilacidece castle test 1.jpg 
Views:	95 
Size:	86.0 KB 
ID:	64400


In keeping with the painting shadows I've started redoing the entire landmass and this is what I have so far.
Click image for larger version. 

Name:	Cilalcidece preview 01.jpg 
Views:	186 
Size:	2.80 MB 
ID:	64401

@TheHorseWhisperer. I tried the SketchUp and it's a really neat program. And I also really like what you have with the Birds Eye city. I do have one question are you going to flatten the 3D project later to create a flat 2D map or are you going to choose a viewpoint and keep the 3D aspect. I really like the 3D idea you are working from but what is your idea for the final image?