SUDBURY - Looking out at a lushly wooded area beyond a stone wall on her 100-acre estate, Carole Wolfe's face darkened. There, in the distance, she said, nervously pointing a finger, stretches a former rail corridor that, if some have their way, could bring trouble upon this town where her family's roots date to Colonial times.

"Instead of solitude," Wolfe said, "you'd be having people."

Wolfe is among a band of vocal Sudbury residents raising the alarm against a proposed bike trail along a pathway where trains once chugged.

Opponents of the "rail trail" say the path would draw hundreds of thousands of bicyclists who would bring with them noise and other disruptions into what is now a pristine landscape. Hordes of bikers, walkers, and rollerbladers would scare away wildlife, they say, and invite crime from trespassing to vandalism and assault.

"We don't have neighbors nearby," said Marianne Maurer, whose family's tree farm is bisected by the proposed bike trail. "If something happened, no one would hear us yelling."

The Sudbury trail would be a segment of the proposed 25-mile Bruce Freeman trail beginning at the Lowell-Chelmsford line and winding to Framingham. With gas prices escalating and alternative transportation increasingly popular, bike trail supporters say their decades-long push for the trail is now a no-brainer. Connecting to major mass transit hubs, such as the West Concord commuter rail terminal, it would provide a good alternative to driving, they argue.

"The public benefit far outweighs any other concerns," said Tom Michelman, president of Friends of the Bruce Freeman Rail Trail, honoring the late longtime state representative from Chelmsford.

The trail would be part of a web of more than 100 miles of bike trails planned for Massachusetts that state officials say could one day permit riders to bike 120 miles from Lowell to Westfield, or along the Mystic River to the beaches of Lynn. The big vision has proved challenging to knit together, with efforts often meeting intense local opposition.

The drive to build the Freeman trail gained significant momentum in October when ground was broken on a portion of it - a 6.8-mile run through Chelmsford and Westford. Concord residents, after a fractious debate at Town Meeting in April, approved a preliminary design for the trail segment that would run through that town. Framingham, at the southern tip of the proposed trail, has just begun appraising, at selectmen's request, the cost of purchasing the right of way owned by CSX Corp. where the trail would run, said Julian Suso, the town manager.

Sudbury remains a holdout. The wealthy hamlet of stately Colonials and rolling farmland, where change comes slowly, could obstruct plans for a continuous path. Opponents of the rail trail in Sudbury - who created Sudbury Citizens for Responsible Land Stewardship to fight the plan - say they are prepared for a lengthy battle. Jim Nigrelli, president of Sudbury Citizens, called the rail-trail advocates "strong-minded"; other opponents are more blunt.