MILLINOCKET, Maine — Lucas St. Clair and the president of the Katahdin Area Chamber of Commerce will hold a telephone town hall event on Wednesday showcasing the proposed national park and recreation area in the region, St. Clair’s spokesman said Monday.

The event is set to start at 7 p.m. Participants can can call 228-1820. It is probably the broadest appeal to Mainers for support since St. Clair replaced his mother, Roxanne Quimby, in 2012 in the family’s quest to donate 150,000 acres of land east of Baxter State Park to the National Park Service in 2016.

“It could be a couple thousand people who call in,” said David Farmer, a former spokesman for Gov. John Baldacci and St. Clair’s spokesman. “We see some momentum building, but there is some confusion about what the park and recreation area would and would not do that we want to clear up if we can.

“This will have a regional and statewide impact. We need to build support for it everywhere,” Farmer said Monday.

The proposal includes a 75,000-acre national park and a 75,000-acre recreation area. Proponents said a park would generate 400 to 1,000 jobs, be maintained by $40 million in private endowments, diversify a Katahdin region economy devastated by the closure of two paper mills, be heavily controlled by local leaders and coexist with existing industries. They say that the park service would draw worldwide tourist support and that the recreation area would guarantee continued if not improved sportsmen’s access in the region.

Opponents have said they fear a park would bring more federal authority into Maine, cramp the state’s forest products industries with tighter air-quality restrictions, generate only low-paying jobs, restrict sportsmen’s access to the Katahdin region and eventually morph into a 3.2-million-acre park plan offered in the 1990s.

They also express skepticism about the positive economic benefits that proponents say the park would create, doubt that the land is attractive enough for a park or that the federal government would heed local concerns.

The St. Clair campaign issued a 10-point list on Thursday that officials say addresses all of the opponents’ concerns. Proponents say with the points incorporated into the federal legislation that would create the park, opponents’ concerns would be addressed permanently. Opponents say that the federal government would eventually change the law.

The campaign has steadily grown since Farmer publicly became its primary spokesman in December. It also hired a local outreach coordinator, Millinocket resident Shelley Farrington, a reporter and former school board member who helps cover the area for the weekly Lincoln News.

Bob Meyers, executive director of the anti-park Maine Snowmobile Association, called the latest activity “a hell of a push, but they don’t seem to be helping themselves too much.”

Despite being years in the making, the park proposal, Meyers said, still lacks many basic details. What roads would be built with it? What lands would have to be taken by eminent domain, if any? What would the park’s features include?

“They are trying to create this impression that something really awesome is going on here, but it’s hard for the rest of us to see it,” Meyers said Monday.

Meanwhile, park opponents such as the Maine Snowmobile Association have told Maine’s Congressional delegation, which would likely propose a park bill before it can happen, of their unwavering opposition, Meyers said.

“I think there is just so much uncertainty with this thing,” Meyers said. “Certainly our political leaders are aware that they are sitting in the middle of a significant and highly funded public relations blitz right now. Everybody looks askance at this.”

Those detail questions probably cannot be answered without input from the congressional delegates, and the interested stakeholders, when the delegates start drafting park legislation, Farmer said.

“We are anxious to work with them when they are ready to start asking those questions,” Farmer said.