WHEN PATRICK HENRY, Thomas Jefferson and other early patriots were laying it on the line for independence, who would have thought that two centuries later the cry from their old stomping grounds would be for interdependance?

Yet such are the twists of history, and that 18th-century cradle of independence called Colonial Williamsburg will be back in the news next month, this time as a 20th-century crucible of economic cooperation.

From May 28 to May 30, seven heads of that many governments and the president of the European Community will be meeting there for their now-annual economic summit. As the early colonists did when they laid the groundwork for a revolution and a new republic, the leaders of the United States, Great Britain, Canada, the Federal Republic of Germany, Italy, France and Japan will on at least one occasion gather in the historic Capitol--which was home to the House of Burgesses, America's first rep-resentative assembly--to voice concerns about what their world is coming to.

And they won't know the half of it.

With an estimated 4,500 to 6,000 journalists attending, in addition to the official summit delegations, the get-together is expected to cost American taxpayers anywhere from $6 million to $8 million. This year it's the United States' turn to host the conference, and as one planner put it, "We want to show off what we're good at in this country."

Exit bewigged quill-penned clerks; enter the cathode ray tube and electronic keyboard, the mini-surveillance cameras and television monitors, the sophisticated hookups for simultaneous translation--in other words, all the accouterments of the computer age to organize and record what goes on.

What posterity may never know, however, is how many thousands of man-hours it took just to get everybody together for less than 72 hours, or the idiosyncrasies of the visiting nations that will keep American summit planners on their toes right up to the end.

"I could never have anticipated, for instance, that the Japanese would want to bring their motorbikes," says Michael McManus, 40, the chief summit planner. As such he heads a full-time, 70-member summit task force detailed from other government agencies that has operated since January out of 1750 Pennsylvania Ave. NW. Later this month nearly the whole crew will move to Williamsburg--some taking their bicycles with them to make quick moves easier.

Nor could McManus have known, until a cablegram arrived the other day, that the French would want a hotline in every room where President Franc,ois Mitterrand will spend more than 15 minutes.

Most of what McManus does know comes from questionnaires answered by summit participants this winter. In them, they specified their special needs/desires/demands on everything from how many private conference rooms are required (the Japanese want nine) to whether their leader travels with a personal food taster.

"Some do," says McManus, though he declines to identify who. At least one will be President Reagan's out in the kitchen, making sure nothing gets put into the food.

McManus, a former New York City attorney, keeps a little list in his pocket reminding himself that by May 28 he must have begged and borrowed, if not actually stolen, the means to transport, house, communicate with, care for and feed everybody who has an official reason to attend the summit. That adds up, at least in part, to the following:

* 200 automobiles;

* 60 to 70 buses for a 24-hour transit system;

* 600 telephones;

* 25 miles of telephone wire;

* two 24-hour switchboards;

* two miles of extra power cables to colonial buildings.

There isn't room on McManus' pocket list for the dozens of other considerations he deals with daily. Last week, for example, he was scheduled to meet with Virginia Gov. Charles Robb about state sales tax. "I'm not sure the federal government ought to be paying state sales tax for a summit in the state of Virginia," says McManus.

And then there is the desire to make this summit a lot more informal and relaxed than the one last year hosted by the French at Versailles. One day recently, he met with Williamsburg's archivist, historian and antique expert to tell them what planners thought the "look" should be in each room where the heads of state are staying and meeting.

"If you've got high-backed old Colonial chairs that are very stiff and straight, people are going to be a little stiff and straight in the way they talk about things," says McManus. "So we're trying to find something a little more comfortable to set a mood."

Yet another detail taking planners' time is the summit table--or the lack of one, since none exists that is large enough to accommodate the leaders and their ministers. That means one has to be built.

"We also have communications requirements with regards to microphones in the table and maybe some way to communicate with someone outside the room," he says.

Also to be renovated, for $1.2 million, is William and Mary College's gymnasium as a press headquarters. One special feature will be air conditioning--unlike at Versailles, where journalists sizzled.

No small consideration is the care and feeding of the free-world egos.

"The whole concept is parity. Everybody needs to be treated equally. That's difficult to do when you've got a house with some rooms smaller than those in another house," says McManus of how the leaders are being billeted in the restored residences around the old village. "So we do it in order of protocol and as long as you follow protocol, everybody's happy."

Feeding several thousand hungry journalists sent McManus off to France last December for tips from the planners of the Versailles summit. Still smarting, perhaps, over criticism that the splendors of Versailles hardly reflected the socialist policies of Mitterrand's government, the French refused to divulge their summit costs. They did tell him that feeding the press had taken a heavy toll on the national purse.

That was enough to send White House planners straight to dozens of U.S. trade associations to seek tax-deductible contributions of food and beverages, another way to spotlight the Reagan administration's heavy emphasis on private-sector initiatives.

"We're going to try to put up a kind of fast food fair on the tennis courts at William and Mary College," says McManus, who envisions a miniature McDonald's or a Burger King, among other possibilities, rising like a Phoenix from the base lines.

Somewhat fancier menus are on tap for France's Mitterrand, Britain's Margaret Thatcher, Canada's Pierre Trudeau, Japan's Yasuhiro Nakasone, Italy's Amintore Fanfani, Germany's Helmut Kohl and the Common Market's Gaston Thorn. They will join President Reagan at the luncheons he will give at Raleigh Tavern and Bassett Hall, the working dinners he will host at Carter's Grove and the Governor's Palace and the state dinner he and Nancy Reagan will give at the Rockefeller Folk Art Center.

Nobody yet knows which, if any, spouses will join the leaders; traditionally they are not invited. Last year became an exception when Nancy Reagan went to France with the president and the White House rebutted a French official who said she had invited herself.

McManus already called in one food expert, author and New York Times columnist Craig Claiborne, to consult on menus that may include U.S. regional fare beyond that of Virginia's colonial times. Last week, White House social secretary Mabel Brandon checked out Williamsburg's entertainment sites..

"The Governor's Palace has some drawbacks," says McManus. "It doesn't have a kitchen or great bathroom facilities or great lighting."

Still, the ambiance of Colonial settings promises to be half the fun with or without knee breeches and wigs, and it was one reason summit planners, including White House Deputy Chief of Staff Michael Deaver, who chose Williamsburg over such places as Jackson Hole, Wyo., and Yosemite National Park.

From the moment their helicopters touch down in Market Square from nearby Langley Air Force Base (after overnight stopovers in Washington), these VIPs can expect to be in and out of time warp. Horse-drawn coaches, for instance, will take them in order of reverse protocol (Mitterrand, as both head of state and government, will come last) to their official welcome by Reagan, waiting at the Governor's Palace, where battery salutes will greet each arrival.

Meanwhile, the public is being advised by Colonial Williamsburg that this year the Memorial Day weekend is not "the optimum" time to visit--in fact, the historic area will be closed to visitors without credentials from Saturday through Monday. Nearby historic areas such as Yorktown and Jamestown won't be affected, however. Williamsburg merchants are eager to avert what happened during the Bicentennial summer, when all the advance talk about crowded conditions scared away tourists and resulted in a business slump for what has become a $200-million-a-year industry.

"We're going to be extremely careful about this short-term time and see that visitors who do come have plenty to see," says Barbara Murphy, president of the Williamsburg Chamber of Commerce. "We're honored that the White House chose Williamsburg for this summit because we realize that the publicity that surrounds this kind of meeting has an impact that is tremendous."

All of the summit planning is a one-time worry for the White House task force. Next year, the summit office will rest on its laurels and advise the British, whose turn it will be. For the president, who visited Britain last year after the Versailles summit, that means the possibility of seeing some old friends. But McManus may be busy elsewhere--on his next project, as White House coordinator for the 1984 Olympics in Los Angeles.