Fairfax County officials and developers of Kingstowne, a proposed $500 million, 1,100-acre new community in southeast Fairfax, are scrambling to work out final details of the complicated rezoning proposal scheduled to come before the county planning commission May 28.

Greendale Development Co., owned by Miller and Smith, a McLean-based residential development firm, has been working on the rezoning for more than a year.

The proposed Kingstowne would be a four-mile-wide new community with jagged boundaries on land east of I-95 and Beulah Street, south of the Capital Beltway between Franconia Road and Telegraph Road.

Plans call for construction of 5,612 residential units, including town houses, patio homes, condominiums and single-family detached homes. Prices are expected to range from $75,000 to over $200,000. Kingstowne plans also call for 2.5 million square feet of commercial and retail space.

Greendale Development has already promised to do more than $28 million in traffic improvements, recreational amenities, environmental protection measures and other improvements in the form of proffers -- legally binding commitments -- attached to the rezoning request, according to Gordon Smith, president of Miller and Smith.

The proposal includes 92 proffers, but county officials estimate the number will likely pass 100 before all details are worked out.

"This is much more involved than a regular rezoning," Smith said. He has been working with Lee District Supervisor Joe Alexander, planning commission member Carl Sell, county planning staff members and the Lee District task force, a citizens group, for a year, Smith said. "Give Joe the credit for a lot of work on this," Smith said.

The proposal for Kingstowne involves three different land-use categories, including development of 894 acres now zoned for planned development housing (PDH) at the highest possible density allowed. The proposal also includes some so-called bonus units.

Greendale also is asking to change a 125-acre site now zoned PDH to PDC, or planned development commercial, and is seeking to change 26 acres now zoned PDH to I-4, or industrial.

The developer also is asking Fairfax to approve development of a 124-acre noncontiguous parcel southwest of Kingstowne for a residential project to be known as Landsdowne. Approximately 74 acres of that site are zoned for industrial use.

Kingstowne plans call for concentrating commercial development near a town center along what would be an extension of South Van Dorn Street, south of where that street now ends near Edison High School.

"This will be a town center, not just for Kingstowne, but for all the Lee District," Smith said. Plans for the center include parks, lakes, neighborhood shopping facilities, a health club, a theater, restaurants and residential units. General office space and high technology-oriented office space will be located near the residential area, Smith said.

If Fairfax approves the project, Greendale will complete major road improvements, including the extension of South Van Dorn Street from Franconia Road through Kingstowne to Telegraph Road. Major parts of the extension are not on the Kingstowne site but must be built to provide a future possible connection to the proposed Lockheed Boulevard that is in the county's long-range transportation plans to link Franconia to Route 1.

Greendale's internal road network will include Kingstowne Boulevard to connect South Van Dorn Street with roads to be built in nearby Manchester Lakes. Village Drive will be built across the four-mile-wide project. Greendale will also have to pay for parts of a spur connecting the area to a planned Metro station at Springfield.

"Once we do all the roads, this project will be a better situation than any similar project in the county. Yes, it is expensive, but once it the road system is there, I don't think there will be a transportation problem," Smith said.

Greendale has also promised to pay for several lakes, tot lots and recreational facilities. Three community recreation centers with swimming pools and tennis courts must be completed on a scheduled tied to the county's issuance of occupancy permits, if the project is approved.

More than 500 of the 1,100 acres involved in Kingstowne will be left in open space, Smith said.

Because of the wide spread in prices -- from $75,000 for a back-to-back townhouse to more than $200,000 for a detached house overlooking a golf course -- Kingstowne is being designed to attract purchasers of every age and income level, the developers said.

Market studies prepared for Greendale said housing in Kingstowne should court the market generated by dual-income small households, while developing houses "to capture a maturing baby boom market with a product directed to second- time buyers in the attached and detached market.

"The phenomenal drop in household size during the 1970s is leveling off. Many who have bought entry-level town houses in the competitive arena over the past five years should be ready to acquire larger townhouses or mid-line single-family homes," the study says.

The study estimates the Kingstowne market should be able to absorb an average of 500 housing units a year. Smith said he is projecting a 10-to-12 year build-out for the project if it is approved.

"Kingstowne, because of its close-in location, its excellent transportation network and the sense of place provided by the town center, will quickly become a new town in its own right," the market study says.

Miller and Smith, a homebuilder in Virginia and Maryland for 21 years, plans to erect many of the residential units.

"We may enter into a joint venture with some other developers. Some parcels will be sold to other builders to get a better mix of housing," Smith said.

"We have visited projects built by most of the major and minor builders in the area. We know what projects we like," Smith said.

"We want a difference in price range. We do not want one builder building in competition with another at the same time," Smith said.

The Kingstowne site includes what was the old 1,000-acre Lehigh Portland Cement Co. site. For many years the land was mined for sand and gravel that existed in natural mounds. Most of the planned site of the town center was formerly the site of a gravel mine and is already graded.

"The gravel was in mounds," Smith said. There was never a quarry operation at the site.

The highly publicized Manchester Lakes development abuts part of Kingstowne. Part of Manchester Lakes is being built on a former land fill, and a cloud spread over the developer after the start of construction because of possible toxic problems on site. However, extensive soil testing was conducted and the tract was given a clean bill of health by the county last year.

Smith said similar environmental testing has been done at the Kingstowne site even though the land was never a landfill or a dump.

Soil and ground water testing by a ground water hydrologist and a consulting toxicologist said the Lehigh site posed no hazards, Smith said.

Eventually, roads will connect Manchester Lakes and Kingstowne.