Correction: An earlier version of this article mischaracterized the scope of plans by the Mitre Corp. for redeveloping the company's headquarters in McLean, Va. The plan consists of one new building and a parking garage instead of three buildings and two parking garages. This version has been corrected.

Michael Caplin, the man charged with promoting the Tysons Corner area as a livable community, extols the virtues of the changing area from atop a hotel. (Dayna Smith/The Washington Post)

He waited in a party van with champagne on ice and a disco ball dangling from the ceiling, ready to sell a vision.

The barren Tysons Corner parking lot just outside looked bleak in the rain, but Michael Caplin saw something else, and after his guests stepped inside and declined the champagne, he made his pitch.

“You can paint the asphalt green,” he told the two developers he hoped would transform the lot that is walking distance from a new Silver Line Metrorail station. “You can set out cafe chairs and benches. You can make it as sumptuous as you want it to be.”

All the while, the architect Caplin brought along was sketching how a parking lot nobody uses could become an instant city park, an oasis where workers could eat lunch. And here it was in ink on paper: tables, benches and a giant chessboard inside a jagged black triangle that offered a taste of how the Northern Virginia neighborhood may change in 30 years.

The developers — who plan to build office buildings, high-rise apartments and retail space near the lot — were sold.

And so went one episode in Caplin’s full-tilt quest to bring excitement to patches of vacant, concrete land that are part of a historic transformation of one of the most inaccessible suburbs in the United States.

Under a plan adopted by Fairfax County in 2010, local and state officials intend to rebuild Tysons Corner in what is essentially a block-by-block do-over of the commercial hub that is home to megamalls, office parks and some of the worst traffic in the region. Even the name has changed, if unofficially: In marketing materials, Caplin’s group dropped the “Corner,” calling it simply Tysons, which county officials embraced as a symbol of the area’s new beginning.

Roughly 20 residential and commercial developments are planned, plus a grid of pedestrian-friendly streets and a network of parks and bike paths that, by 2050, would make Tysons home to as many as 100,000 people and 200,000 jobs, officials say.

Divided into eight villages, the area would also include a new fire station, a police station, schools and a museum or performing arts center, county officials said.

Caplin, 62, is the impresario of that effort, promising wonder.

“Everybody knows this can become the Emerald City of Oz,” said Caplin, the head of the Tysons Partnership group of businesses and other stakeholders. “It’s got the potential. It’s going to be dazzling.”

But for now, Tysons is as congested as it ever was, with about 100,000 cars a day, and some doubt that the effort to re-create the area as a pedestrian-friendly downtown will work.

Caplin and others are trying to create a sense of place in an area that by the evening rush hour most people are eager to leave.

How those efforts take hold could determine whether Tysons becomes a destination neighborhood that helps lift the Washington area for decades or a failed experiment that further contributes to the region’s deepest problems, urban planners say.

Many of the long-term projects planned are years away from breaking ground and, in a competitive real estate market, even further than that if the economy dips again.

Moreover, the street grid and other amenities will be paid for by developers and are, therefore, subject to their schedules. That puts Tysons in a fragile period, where the perception of what’s coming plays a vital role in its ability to succeed, planners and officials say.

“There is sort of a chicken-and-egg situation here, where the developers are waiting to make their next investment, but [before they do] they want to have the confidence that the public sector is there, committed to helping them with place making,” said Stewart Schwartz, director of the Coalition for Smarter Growth in the region.

In collaboration with developers and local officials, much of Caplin’s efforts are focused on the Silver Line’s first day of operation, a coming-out day for Tysons that has been delayed several times. Riders on the train will be greeted by a festival or series of celebrations at each of Tysons’s four stations, he said.

A former Justice Department prosecutor, entertainment lawyer and strategic planning consultant, Caplin is a man bursting with exuberance.

Some of his ideas have fallen flat — like the one in which he tried to persuade a Metrorail official to allow someone dressed as the Lone Ranger to pass out phony silver doubloons to passengers as a way to promote the arrival of the Silver Line.

“She looked at me and said, ‘People under 40 don’t know who the Lone Ranger is,’ ” Caplin recalled. “I was so bummed out.”

Other projects are out of P.T. Barnum’s playbook.

On one recent morning, Caplin was on the roof of the Courtyard Marriott, one of the highest points in the area that straddles the communities of McLean and Vienna.

Before him, the Silver Line tracks swooped in from Washington and construction cranes sliced into the skyline as the hiss of constant traffic echoed below. Caplin’s sights were fixed on a plain gray wall in the middle distance, where he plans to convert a vacant parcel of land near the Tysons Galleria mall into a makeshift town square.

The wall is where lights beamed from the hotel roof and two nearby buildings would converge into a giant work of art, he said. The tops of surrounding buildings will also be bathed in light for what Caplin described as “that big ta-da moment” for Silver Line riders arriving from Washington.

The stagecraft is meant to gloss over what many still see as a soulless landscape of concrete and asphalt, with potential new headaches approaching.

There’s the aesthetic problem of the elevated Silver Line tracks themselves, which turn toward Reston on massive gray concrete pillars that loom over Routes 7 and 123.

In 2008, Metro opted against building the tracks underground to keep costs down for the $5.6 billion Silver Line extension.

Now that they’re up, the tracks are such a “tangle of concrete” that they may deter people from moving to Tysons, said Sol Glasner, general counsel of the Mitre Corp., a nonprofit government contractor that recently broke ground on plans to build an office tower and a parking garage in Tysons.

“It can impede the realization of the vision,” said Glasner, also the chairman of Tysons Partnership. “It can seriously slow it down.”

Sharon Bulova (D), chairwoman of the Fairfax County Board of Supervisors, said she is arranging a meeting to discuss ways to make the pillars more appealing.

“When I first saw the Silver Line infrastructure go in, my heart sank and I thought: ‘Ack. Why didn’t we do something with the concrete to make it more attractive?’ ” Bulova said. “I would like to think that Tysons is going to be a great city, and all great cities incorporate aesthetics and incorporate beauty into their community.”

Caplin hopes to decorate the pillars — cascading colors, perhaps — but Metro officials have demurred on doing anything with them, though they plan on installing art at the four Tysons stations, a spokeswoman said.

Another obstacle is the growing resentment over resources being poured into Tysons. Homeowners already worried about spillover traffic oppose plans to partially fund the new Tysons roads with state tax money meant to relieve congestion in Virginia, said Sally Horn, president of the McLean Citizens Association.

In Vienna, residents complain that the Tysons transformation is fueling higher-density development in their community.

A woody area near Spring Lake has been the site of several multi-house developments built on land that used to have just one home, said Jeanne McVey, who is leading a local fight against plans for a nine-house development.

“This new Tysons is really for the future residents; it’s not for the people who are here,” McVey said. “Talk about ripple effect. It’s going to look like crap.”

Caplin acknowledged that a new city probably means new city problems, such as homelessness and crime.

“It’s naive to think that a place that is going to increase itself by 100 percent is not going to get some big-city issues,” he said.

But standing on the hotel roof, he painted a verbal portrait of what the area will look like in 2050 — his hands pulling up imaginary buildings that are now just plans on blueprints.

Across Route 123 stood a lonely parking lot near the Tysons Corner mall, which laid the foundation for what’s there now when it opened in 1968 as one of the country’s largest indoor shopping centers.

“That’s going to be our Rockefeller Center,” Caplin said.

“It’s going to be full of vitality, with cafes around the edge, and it’s got a green hill on it, and there’s a stage where they’ll have entertainment. And they’ll be trees, and there’s a green hill where you can put a blanket and a sandwich,” he said, his voice rising with delight as a truck blared its horn below.