This cache is located just off the Ellis Bog Trail, which begins at the back of the parking lot of Sanctuary Church. You can park there or in a small town-owned lot just west of Sanctuary's parking lot. The walking trail in either lot will get you there. It's a medium sized rectangular lock-and-lock container. I put some goodies in there for the FTF. Should be plenty of room to leave trading items.
The trail leads to the Ellis Bog, which is no longer operational, but neighbors help keep the trail around it neat and tidy. There is the occasional dog walker, but usually it's pretty quiet. A blue heron and an egret hang out around the pond during the summer. There are also tons of turtles and all sorts of amazing birds and bugs (including ticks and mosquitos, so plan accordingly).
Good luck!