This is the best zoo I've seen in the central New England area. Just an hour from central Mass. This zoo is nice and flat for the most part, so if you're using a stroller, it's much easier, particularly with multiples! They do rent strollers too. They always have events going on. Halloween is great there.
I just checked out the website again (we usually don't go in the winter) and they are working on a big renovation, but still open. So it'll be even better!!!
There's also a carousel in another area of the Roger Williams Park outside of the zoo, but still on park grounds. We haven't been to the carousel yet because we've spent our whole day at the zoo.
Back to the zoo, they have a small lunch restaurant (fast food), but I'd recommend you bring your own if you can (no straws allowed). We love this park also because it's clean and the animal exhibits are awesome. They also have a gift shop.
It's very easy to get too, right off the highway (I-95). When you drive down the long driveway into the park it's hard to believe you're so close to a major city. It's quiet too! We love this park and it's worth driving a little further out of Massachusetts (way better than Southwicks!!)