One more option, Tobit:
Park at the town line sign (Bald Knob Trailhead) and hike up Bald Knob (it's really not bad as it is steep but short and has nice stopping points/views on the way up), hike the carriage roads/trails, as described, to Turtlehead. Don't miss the columnar jointing exhibited in the rocks on the summit. Then return by the same carriage roads to the Bald Knob Cut-off and hike that down to the Shannon Brook Trail, stopping on the way to see the more exposed jointing on a short side trail to round out your geological excitement. Take a left on the Shannon Brook Trail and follow it to the road. Walk the flat road, less than a mile, back to your car. Main benefit is much more variety to the trip but also almost all the work is over after the first mile. Walking the carriage roads is a breeze.
My son and I did this trip easily last summer. He is not in primo shape and found it a reasonable outing.
Whatever route have fun!