A copy of the CT Walk Book West is highly recommended, available from CFPA or at local bookstores. This book shows all the CT Blue-Blazed Trails in the western half of CT.
11. Plainville. Bring your markers. Above Crescent Lake, just north of Sunset Rock, the trail now splits. Take the old Metacomet route, now blazed red/blue, and detour to the top of Bradley Mountain. With your back to great views of West Peak (Sleeping Giant in the background), head straight to a rocky knoll capped by a hardy twin oak with SPOR. Stamp in at the overlook and use whatever colors you see in the vista before you.
12. New Britain. A major 2009 reroute is not reflected in my copy of the CT Walkbook, so read here for info and map on the new reroute. And more ;). Precisely half way from the new trail junction to the new trailhead at Esther Street, find the BIG black birch kinked out over the trail. That would be a mile from either end. It's pointing to a leaning twin across the trail that hides your treasure in her feet. In retrospect this box turns out to be technically located in Plainville -- the New Britain line is about 500 feet down the trail. I prefer the hike coming from Bradley Mountain/Crescent Lake above rather than from Esther Street down below.
13. Farmington. A friendly reminder to always check for snakes before sticking your hand in some nook to retrieve a box, especially on this mountain, which may be infested :D. Take the trail up the knoll above the cave where the legendary sheep thief lived, and look for the largest tree, an oak. When you're done, please replace the trap door carefully and throw a few leaves around the edges so it looks natural. Just a bit further south is a beautiful view, I hope you check it out.
14. Avon. At N41° 46.277', W72° 48.011' there is a big leaning oak with nice roots for hiding things, about 50 feet off the trail. It's located at the supposed viewpoint on the map at right (maybe in winter?). If you come across the giant trailside bolder that Zeus split in half , you are about 175 feet too far south down the trail.
15.West Hartford. Half way along Reservoir 6, there is a sign that marks the city boundary. Less than 100 feet away and not far from the trail is a large triple pine (the sisters are apparently very devoted to each other). (update: I'm told the triple is now a large double stump).
16. Simsbury. On King Philip's scenic overlook, two iron pins are nestled in a bed of Bearberry about mid-way along the overlook. Straight down from the pins, find a small log nestled up against a Chestnut Oak. Don't trip over any tupperware. Continue on to the boulder. Rehide really well please!
17. Bloomfield. Veeder and his guests climbed the Stairway to Heaven back to the cabin, and enjoyed the amazing view from the Pinnacle. But Veeder craved some time alone and decided to go to sit at his private little overlook for a spell. He followed the blue blazes north for 10 or 15 minutes until he came to the big ramp-jump rock crossing the trail. It was about 5 minutes before the deep valley. If he had wheels the ramp-rock could lift him upwards into the air! He walked around the ramp-rock to the right, and then it was only another 250 feet, where the trail leveled off, when he spotted his marker oak -- the one with a low burl about 25 feet off the trail to the right. Veeder smiled and went left to the mossy ledge and sat down. Now he had a clear view across the Farmington Valley, and it was all to himself! Time to jots some notes in the secret journal he kept under the tree. It was to his left, leaning uphill slightly, with enough exposed roots to hide his secrets.
18. East Granby. After enjoying the Tariffville Gorge overlook, follow the blazes uphill until they do a 180 (pay attention!), then another 75 feet to a pair of dancing trees. Ginger Rogers leans back into Fred Astaire's arms (he's the twisted black birch). Look downhill to a big old wolf tree and check the left side just behind the big fallen limb and under a rock.
19. Suffield. Find the granite survey monument that marks the boundary between East Granby and Suffield. From Phelp's Road, wander on up Suffield Mountain to the overlook with the bench, trail-book, and granite monument, then continue on for about 15 minutes, down into a deep ravine and then back up, and pass through a stone wall. See the monument on the left after another minute, just before the dramatic hemlock jutting out of a rock directly ahead. From the monument, go 30 steps at 48° to a twin maple with character. There's a nice overlook nearby for stamping in.
And that's it for Connecticut! There are more NET-themed boxes in Massachusetts listed by Wanda & Pete.