Yea, I think some will be along the first few scenes and/or near the queue building entrance... But I bet the bulk of it will be for a giant cave that will kind of frame the entire back of the ride area, creating a towering backdrop as seen from Hogsmeade and the ride entrance paths.
EDIT: So, thinking of this three-dimensionally, as seen from Hogsmeade's ride entrance: We'll see trees in foreground, rockwork, trees, big castle-style arches, bridges and other structures, more trees, giant rockwork farther away looming in the distance, surrounded by more trees. It should be quite a sight.