We've visited the West Hartford Children's Museum several times. It takes one hour exactly from our home, and is very close to the highway so it's easy to find. Parking is free, and though the lot has often been crowded I've always found a spot.
This museum really is a kid pleaser. A physics oriented room painted vividly is a big draw. Other features: A large fossil dig area with goggles and dress up vests, a surprising number of live animals (many snakes, lizards, turtles, and a few small mammals), a lego room, a toddler area, and some other fun nooks and crannies. The outdoor space is disappointing here, and I haven't seen much improvement over the course of my visits - though I allow there has been some. A dinosaur themed mini golf area had really gross old water that the kids kept fishing golf balls out of. My friend and I were appalled. Really Gross.
You can choose indoor seating for your snack, next to some exhibits and basic vending, or outdoor seating at picnic tables under a shade tent.
Admission is FREE with your Springfield Quadrangle membership.