The area is guarded by robots and part of the quest “Special Delivery”. In the laboratory, there’s a Zeta Gun on the table and a chem station nearby. Edward’s room in the basement has a Fat-Man, Master floor safe, green steamer trunk, and mini-nuke on top of a cabinet.
Later after you finished all quests involving the Cabot Family, you can return to the house and access the previously inaccessible rooms. One of the rooms in the upper room has a green steamer trunk and one of the bedrooms to the east has an issue of Massachusetts Surgical Journal.