Holy Holly Hill!

David Turner, a soft-spoken and very kind-faced 51-year-old Westchester real estate broker, stood in his black fleece Columbia vest and Merrell shoes in something called the Love Temple, a pavilion in the perfectly manicured southwest section of a 64.6-acre estate.

Rain fell. Wild turkeys shuffled by. An owl hooted. It was like a Victorian novel, except Victorian novels end with marriages, and the main story at this infinite estate, Holly Hill, ended when the regal philanthropist Brooke Astor died here last year at age 105. She was survived by one son, Anthony Marshall, a handsome ex-ambassador who has pleaded not guilty to a 16-count indictment accusing him of stealing his mother’s fortune while she suffered from Alzheimer’s.

“I try to stay away from that and sell the property—present it in the best light so we can get the most money for it. I try not to be distracted,” Mr. Turner said. This week he is listing the property, on Scarborough Road in Briarcliff Manor, for $12.9 million.

“Oh! Oh! There’s a deer,” he said, driving his BMW along the road that leads from the gardener’s cottage (with four bedrooms) to the chauffeur’s apartment (atop a five-bay carriage house), to the ancient pump house, to the barn (with a three-car garage), to the small museum, to the hefty but empty greenhouse, to the root cellar, to the pet cemetery.

And those were on the car’s left. On the right were the cutting garden, the holly hedgerows, the outdoor pool overlooking a meadow and croquette lawn, the apple orchard, and that Love Temple. Deer actually frolic in the orchard.

“Look at that buck,” Mr. Turner cooed. “That is a good-sized buck. That is a five-point buck.”

Mr. Turner has two topographic maps in the BMW that show how a potential buyer might build either one or three new houses and pools. He and his colleagues at Sotheby’s International Realty “have relationships with lots of developers,” he said. “We are, of course, going to show it to them.” The estate has not opted to create a conservation easement, which would, as he says with a shrug, “give up development rights forever.”

But no postmillennial house could have the ancient poise, grandeur and symmetry of Astor’s 24-room, 13-bedroom, 11-bathroom stone house, built by William Adams Delano in 1927. Unlike the Astor duplex on Park Avenue, currently listed for $34 million, it’s still saturated with her imperial belongings: The first thing you see, after the vestibule’s cane rack, is a Presidential Medal of Freedom hanging on the left of the marble foyer.

The vestibule leads to the 42-foot-long parquet-floored drawing room, which leads to a sun porch called the Philosopher’s Room, which leads to the indoor pool, still pale blue but not the 90 degrees that Astor liked.

Then there’s the photograph-covered Memory Room; the wet bar (with Tabasco and bitters); the slightly scary one-person elevator; the library; the dining room; the second sun porch; the butler’s pantry; the kitchen; and the four-room staff quarters, which are a relatively dour new addition to Delano’s house.

Walking from the second floor’s balconied master bedroom suite to the Cardinal’s Room (telegrams from the Vatican are on the wall) to a primly twin-bedded guest bedroom, Mr. Turner concedes that his biggest listing until this week was a $15.75 million house in Bedford Corners that went down to $11.75 million, but hasn’t sold.

On the bright side, he broke local real estate records in Chappaqua, where the Clintons own a home, when he sold a hilltop brick Colonial this summer to the Upper West Side market heiress Ann Zabar for $8,372,500. Still, almost everything is having trouble selling these days, including the Astor duplex on Park, recently price-cut by $12 million.

(That duplex, like Holly Hill, has apparently been bequeathed to Mr. Marshall, but neither is actually his yet because of the ongoing criminal case.)

And yearly taxes for the Westchester estate are now a stupefying $199,000, according to the broker. “I think if someone’s worried about the taxes on this property,” Mr. Turner offered, “they can’t afford to buy it.”

mabelson@observer.com