"The SRK Greenway is a 75-mile loop of hiking trails in central New Hampshire. The Greenway Trail System circles the Lake Sunapee area and connects Sunapee, Ragged, and Kearsarge Mountains."

The SRK Website contains section maps and trail descriptions,  and info to purchase a tyvek map of the entire Greenway. I found the little map to be very portable and durable, and I would also read the online section guide before doing each section. https://www.srkg.com/

Percentage runnable: 65-80%

Elevation change: lots of ups and downs

Ease of Navigation: Most of the trail is well- marked with white, trapezoidal metal or painted blazes. Occasionally the trail is hard to follow when it passes through towns or coincides with wood roads.

Parking areas: clearly indicated on maps and in trail descriptions. Some parking is not usable in the winter. 

I enjoyed many section runs, alone or with one of my kids, over the last 18 months or so, finishing my last segment at the high spot of the top of Sunapee. Some of the sections include a lot of road running, most notably from the center of Sunapee village to Deer Hill Rd., which is ALL road (trail 3). I found the prettiest/smoothest running segments to be: Section 2 in Sunapee, from a small parking area on Harding Hill Rd., through the Webb Woods to Tilton Park (5.5 miles, would make a nice out-and back); trail 5 from 114 in Springfield to Pleasant Lake in New London (8.4 very hilly miles, might be a nice one to do with a friend and two cars), and Trail 6, from Pleasant Lake in New London to the summit of little Bog Mountain in Wilmot (4.2 miles, another nice out-and-back).  It is probably better to do in the summer or fall: I tried a few segments in the winter and either had parking problems or navigation problems (hard to see the white blazes when they are covered over by fresh powder).