Wow! Thanks for sharing! So much interesting stuff in that concept art. Street of Dreams has me curious. Anyways, judging by this, it looks like moving the castle to the back would work very well, and I almost feel as though it will work better. They could open up the area where the castle currently stands by adding turrets there. Think the turrets by 7DMT in New Fantasyland in Magic Kingdom except in front, and themed to match the design of the new castle. Then you enter Fantasyland and off in the distance is the new castle. I could also see them adding a ride of some sort in the castle if they did this. I also think that a further back castle would mesh with the mountains better.