This is a very easy paved rail trail that starts near the Massachusetts border. It encounters several road crossings as it travels south, but the crossings are well marked and recognized by motorists. This is a great option for families, with many places to access the trail or turn around early depending on your desired mileage.
There is one section of the trail in Avon, CT where you run on the sidewalks or side of the road. Plenty of signs help you find your way back to the trail, and if in doubt, you can use the Trail Run Project mobile app
to guide you. For some reason this short section has not been completed (private land?).
Near the middle of this section is the "Plan B" restaurant in Simsbury, CT. The food is great and they have a good selection of microbrews! There is also a small park with a playground for the kids and ample parking.