If you have small children in your party, check out Nelson Memorial Park in Plymouth center. (it's just up the coast of Plymouth Long Beach, north of Plymouth Wharf). Nelson Park has a nice splash park (perfect for kids not yet of swimming age), a playground (slides, swings, climbing ropes, etc.), shade trees, picnic tables, a concession stand (snacks, pizza, hot dogs -- even sun block and diapers), food trucks for lobster rolls and ice cream treats, clean rest rooms, and a nice beach facing Plymouth Bay. Parking is available within a few blocks if the park's parking lot is full. We went back 3 times in one week.