Radnor's purchase would create a 200-plus-acre park for the heavily developed community, said Spingler, who has pushed for the purchase for years.
"The good news is, eight years ago, we were going to pay $21 million for it," he said.
The deal would require the approval of the Board of Commissioners, which will present the agreement at a meeting Monday night and schedule public hearings.
Scott has already built 10 high-end houses on the 311-acre family estate and has long sought to develop more. He has said he intends to preserve the historic mansion, designed by Horace Trumbauer, and 10 surrounding acres.
Some residents maintain the township is paying too much for the land, which is held by two trusts that have represented the Montgomery, Scott, and Wheeler families for six generations.
Leslie Morgan, a commercial real estate developer who lives in Radnor, said that because Scott was seeking a density modification for his development, he was required to set aside a portion for open space.
Part of the land the township wants to buy could count toward that open space, she said.
"The zoning process has been seriously compromised because of our Board of Commissioners waving a check," she said. "This would never be a question with another developer."
But Elaine Schaefer, president of the commissioners, said Scott wasn't required to set aside the land Radnor wants preserved.
"The developer can put open space anywhere he or she sees fit," she said.
She also said that if Scott wasn't "getting value" by selling part of his property to the township, he could end up building more houses.
"We've been working with him for seven years to come up with a solution where he can minimize the density of his development and we can preserve open space," she said. "This is something our community has wanted for years."
Scott said that if he didn't sell the land to the township, "I'd sell the land to somebody else. It's a lovely property. I would imagine that a lot of people would be interested in it."
The three parcels are the 16.3-acre quarry tract adjacent to the Willows; the 27-acre Rye Field, across the street at Darby-Paoli and Newtown Roads; and the 27.65-acre Wheeler tract by Sawmill Bridge.
The township plans to pay for the property with a $10 million bond issue, $1 million from the state Department of Conservation and Natural Resources, and other funding.
Spingler said the bond would cost residents about $50 to $90 more in taxes each year.
Officials plan to install some trails on the properties, but not much else will change. Even a farmer and his cows, a longtime feature on Darby-Paoli Road, will likely remain.
"We want to keep a little rural character," Spingler said. "We're not looking to put ball fields and lights. We want a nice park setting."
"A hundred years from now," he said, "they're going to say who had the foresight to do this."