Looking good so far, though I think you could probably inject a bit more color and vegetation/overgrowth in there to break the monotone color scheme right now while still retaining the decayed and gloomy feeling of it. Maybe push the Fall season aspect of it given the orange leaves you have there?
@yubbie: Thanks, those are some great references that I will definitely be using. @deceiver: I will definitely have to rework and experiment with the colors to get the monochromatic feel of the concept, all while keeping the abandoned/decayed feel. This was actually my first concept that I did just to get something on…