The project would bring to the peninsula a mix of 20 to 40 small retailers - restaurants, franchises, and specialty shops- two mid-sized retail anchors, and a stock of condominiums and rental residences. The residential units would be located both above retail space and in freestanding structures whose height might stretch well above that of current buildings on the peninsula.

"Our orientation is to make a place nice and unique enough to give Dorchester new face in the marketplace," said Richard Heape, of Streetworks, a company that has been enlisted by Corcoran Jennison to help design and manage the redevelopment.

While the plan at this point is very general, Joseph J. Corcoran said that a timeline for recruiting retailers and clarifying the plan will move quickly, with a goal of applying for initial permitting early this fall.

"We're anxious to get started," he said. "We have a business that's not doing well, and that is really driving our timeline."

The fate of the property, currently home to the Bayside Expo Center, has been a source of speculation since last summer, when state legislation allowed for the trade shows on which the center depends to be held at the much larger Massachusetts Convention and Exhibition Center in South Boston, effectively eliminating Bayside's business base.

The plan would leave intact the Bayside office center and Doubletree hotel, as well as the independently owned Boston Teachers Union. The Harbor Point residential development, which was built by Corcoran Jennison and is co-owned by the company and the development's tenants, would be unaffected.

Heape said that a mid-sized grocer -like a Whole Foods or Trader Joe's- would be crucial in bringing reliable off-site customers to the new development. That and other larger retailers would likely be situated closer to Morrissey and the MBTA's Red Line station, with denser residential development near the waterfront and a cluster of mixed-use urban streets in between.

"We're not looking at any store above fifty or sixty thousand square feet," said Heape. "Any other store would be no more than half that size, maybe thirty thousand square feet."

A crucial challenge to planners will be redesigning pedestrian traffic from the T station and automobile traffic on Morrissey Boulevard and in the chronically conjested Kosciuszko Circle.

Heape said that creative solutions to those problems may make it unnecessary to completely reconfigure streets around the development.

"It's a problem not in volume, but in geometry," said Heapes, of automobile traffic around the peninsula.

The plan was unveiled Thursay morning at a meeting of Dorchester elected officials and neighborhood leaders.

"People are cognizant that this use [the expo center] isn't going to be here anymore," said Corcoran. "They have been fairly accepting of the fact that something else is going to be here, and there doesn't seem to be anyone offended to date."

As Corcoran Jennison and Streetworks proceed, consulting with city and state agencies as well as courting retailers throughout the summer months, the developers will also embark on a community process begin a community process to inform and seek feedback from Dorchester residents and civic leaders. The first community meeting will be held on June 20 at the Bayside Expo Center.