Went on a hike a couple of weeks ago along the Reservoir Trail in the Western Middlesex Fells in Winchester and Medford. It was a decent-sized group, with about 15 of us on the hike. Part of the hike included a quick lesson on geocaching, as there are a couple of spots along the Reservoir Trail where items have been left for those who participate in this.
The Reservoir Trail isn't as scenic as the Skyline Trail, which loops mostly parallel to the Reservoir Trail in the Fells. But it is an interesting trail, with frequent water views and hikes through scenic wooded terrain. All in all, a fairly easy, pleasant 6-mile hike.