This is my understanding of the "Be Our Guest" restaurant:
You will enter over a drawbridge structure (like in front of Sleeping Beauty Castle at Disneyland) to the entrance foyer which is built into the side of a mountain. To the left of the drawbridge is Maurice and Belle's cottage where you can meet Belle, and to the left is the village, home of Gaston's Tavern. Above and behind the mountain is Beast's Castle, as if off in the distance, similar to the way the Eiffel Tower is presented in Epcot's France pavilion. As the Eiffel Tower is visible throughout World Showcase, Beast's castle will be in Fantasyland. It will be very difficult to find a sightline where you can compare it with Cinderella Castle without it appearing to be just further off in the distance.
Through the entrance/foyer you'll enter the Ballroom and the main seating area. Smaller dining areas are to the left and right. The kitchen is on the left, bathrooms on the right. The ballroom will look like the one in the film, with a large curved window area in the rear. The trick will be to keep the window area from allowing a view of the backstage area. Right below will be the road used by the buses bring Cast Members from parking to the Utilidor, as well as delivery trucks. This should be below grade level so keeping sightline up could do the trick. Directly behind this is a new pond and some of the old trees that separate this area from the railroad tracks, so it may not be as difficult as I think.
Understandably, the restaurant dining rooms are within the mountain, similar to LeCellier in Epcot. The illusion will be you are dining in the castle in the distance.
Currently (10/13) steel work is rising in the Kitchen section, with excavation and foundation work for the main ballroom progressing. As mentioned, this is going to be a very large building.