William G. Rantoul, of the Boston firm Jacques and Rantoul, served as the estate's principal architect, creating most of the original architecture in the years 1895-1910. He designed the 72-room main house (demolished 1955) and houses for the coachman, forester, and head gardener. A second large house was built 1939-1941 for Helen Moseley, Frederick's younger daughter. In the early 1950s the privacy and remoteness of the estate were diminished with the construction of Route 95 through the middle of upper woods and the contemporaneous construction of Route 495 at the top of the left bank of the river, both of which became major routes for heavy trucks. Highway noise in the park during business hours is insistent. On the death of the Moseleys the family had the main house torn down. In 1978 Helen's house was destroyed by fire. Today only few of some 30 structures remain.