Northeast (MA, CT, RI, ME, NH, VT)

Wikipedia: Regicides Trail is a Blue-Blazed hiking trail, about 7 miles (11 km) long, roughly following the edge of a diabase, or traprock, cliff northwest of

Alex McDaniel posted an initial route and FKT.  He wrote:

The Blue Hills Skyline Trail is located in the Blue Hills Reservation, in Milton, MA, just minutes from downtown Boston. The Reservation covers 7,000 acres of rugged, forested landscape. There are an amazing 125 miles of trails in the Reservation. A 2-page brochure with trail map is here. The classic trail in the park is the 9-mile, blue blazed Skyline Trail.

This is a Premier Route. To claim an FKT on this route, you must meet a high standard of documentation and verification. See details here: https://fastestknowntime.com/premier-routes.

“The Long Trail: Where even the downhills are uphill.” - Alicia Hudelson

This route is local premier route for the single traverse (both directions are options).

The Monadnock-Sunapee Greenway Trail (MSGT) is a 48 mile long hiking trail that links Grand Monadnock with Mount Sunapee in southwestern New Hampshire. It winds along the Monadnock Highlands that divide the Connecticut and Merrimack River drainages. It is maintained by the Monadnock-Sunappe Greenway Trail Club.

The Appalachian Trail through Connecticut, about 51 miles.

This route is a local premier route.

The Presi Traverse southbound is a Premier Route. To claim an FKT on this route, you must meet a high standard of documentation and verification. See details here: https://fastestknowntime.com/premier-routes.

This route is a local premier route for the single loop, while there are many other variations available.