Extended and adjusted version of Cragmaw Castle from the Lost Mine of Phandelver module. I added some exterior area and moved the castle to the top of a hillside. I think this made approaching the castle more interesting and provides some more room to play out how the players get in.

The western entrance is open, fortified and potentially guarded, leading by the worg kennel outside. The northern entrance is blocked off by a lowered, wooden portculli, which could potentially be overcome with a high strength check or it could be broken through by the freed owlbear. The eastern entrance can be reached via a winding cliffside passage, potentially secured by a guard or a trap.

The room and door arrangement inside has been changed slightly, having the chamber with the owlbear open up into the main passage for example made more sense to me as the original.