At Mike's Pastry, legendary purveyor of cannoli in Boston's North End, workers are gearing up for restive nights when the Democratic National Convention comes to town Monday.

Rather than forcing them to brave a gantlet of highway and rail closures to commute to a neighborhood near the convention site, owner Mike Mercogliano invited as many as 10 employees to crash all week in a basement studio apartment and upstairs annex two blocks from the shop.

"It's basically gonna be a dormitory," said Richard Martins, of Medford, who added that his usual half-hour commute to work would more than double next week. "But we can put up with anything for a few days. Otherwise, we have to deal with the chaos."

All over the city, as convention organizers put the finishing touches on the Democratic Party's big event, area residents are preparing for what some observers predict will be one of the most significant disruptions of everyday life some parts of this city have ever seen.

Security concerns are forcing the closure of 40 miles of roads and major highways leading through the city, from about 4 p.m. until after midnight from Monday until Friday, including a large portion of Interstate 93, known here as the Central Artery, which runs within 40 feet of FleetCenter, the convention site.

North Station, one of the city's two main train hubs and the point of entry for 25,000 daily commuters, will be closed from Friday night until after the Democrats have left.

Passengers on the Orange Line subway, which terminates at FleetCenter, will be barred from carrying packages on board that are larger than a loaf of bread, while riders throughout the city's subway system, known here as the T, will be subject to random searches, and those hoping to take luggage to the airport will be asked to show plane tickets.

Trying to ease people's minds, officials at a City Hall news conference last month declared there was no need for panic because the city has weathered a storm such as this before: the Blizzard of 1978, which paralyzed much of New England with two feet of snow.

Mayor Thomas M. Menino (D), who fought to bring the convention to Boston, has encouraged workers to take a vacation or telecommute, as City Hall added the less-than-enthusiastic slogan "Let's Work Around It," to its convention PR campaign.

For delegates, most of whom are staying in downtown hotels, the inconvenience will probably be minimal. "It's a walking city, so people will be able to get around, even if the traffic is terrible," said Jack Corrigan, the convention liaison for John F. Kerry, who will become the presidential nominee.

But just about every local commuter and store owner seems to be plotting a course through the four-day event.

On a recent afternoon, employees of Hilton's Tent City, two blocks from the FleetCenter, joked about how their camping gear might come in handy if they are unable to get home. But manager Tony Staffier said traffic might not be as bad as predicted if commuters are scared away.

"It's like Y2K," he said. "They've done such a good job of hyping it that it'll probably be no big deal."

Joanna LeBlanc, who works next door to FleetCenter in the Thomas P. O'Neill Federal Building, wanted to skip town next week as five of her seven co-workers are doing, but she only had a half-week of vacation. Her solution: leave every day at 1 p.m. to beat the evening rush.

"I haven't found anyone who can tell me how long it's going to take to get in," said LeBlanc, 40, of Malden, a city north of Boston. Although the commute usually takes 40 minutes, she will leave the house at 5:30 a.m. for an 8 a.m. shift.

Mike Krakofsky, 24, of Chelsea, a Boston neighborhood north of downtown, slings pies at West End Pizza a few blocks from FleetCenter. He said he is one of the lucky ones. His boss booked a hotel room for two or three employees in nearby Quincy Market. "It's better than sleeping on the counter with paper towels for a pillow," Krakofsky joked.

How all this will affect businesses in Boston depends on the study. The Beacon Hill Institute, a think tank affiliated with Suffolk University, originally projected that the revenue generated by the 35,000 expected visitors would be a $122 million boon to the city. Menino's office estimated that figure even higher, at more than $150 million.

But after learning of all the road closures and other logistical hassles that could hamper the operations of downtown businesses, the institute revised its estimate and now projects a net $8.2 million hit for the local economy. The mayor's office has stuck by its figure.

Some businesses are clearly expecting to cash in. Many restaurants and bars are booked solid all week or expect a steady flow of convention traffic. But those that depend on regular, local customers are less optimistic. Another Beacon Hill Institute study, released Monday, found that overall only 11 percent of Boston businesses expect the convention to help them earn more money.

Ralph Terrazano, 41, of the Valenti Ticket Agency, which sells snacks, tobacco products and tickets to sporting events, said he expects little business during the convention because visitors already have evening plans and will be leaving town soon after the convention ends July 29.

Martins, of Mike's Pastry, said he thinks the costs and benefits of the convention will cancel out each other. "We may get a few extra people coming in, especially for a weeknight," he said. "But we've also been told by our suppliers that they won't be making any deliveries here next week, which makes things hard."

Virtually every individual and institution in the city seems likely to feel the impact somehow. The Massachusetts bar exam will be held on the last two days of the convention, adding a layer of complication to a stressful event. The state Board of Bar Examiners recently posted an alert about the transportation situation on its Web site, and asked test takers to "please plan accordingly."

Massachusetts General Hospital, less than half a mile from FleetCenter, has canceled all elective procedures and drastically scaled back its clinic schedule for the week, to avoid subjecting patients to the travel hassles and to free up space in case of an emergency.

It could be a relaxing week, with fewer patients to handle than usual, but Jenia Paniagua, 25, a medical assistant in the hospital's Cancer Center, is not taking any chances. "I'm out of here," she said. "I'll be in Florida."

For visitors, tight security measures are expected, such as police dogs at an Amtrak station.Road closures for the convention will change the way many travel in Boston. Some businesses have posted their displeasure.