Going to the Braintree Watson Park splash pad is like a day at the beach, without the sand. Parking can also be like beach parking, with a long death walk in the sun. But persevere, you're kids will worshsip you when you get there and it makes for great leverage. Unfortunately for Mom, Dad, or whoever, it's not going to be much fun on a sunny, hot day. You will fry and become completely annoyed as there is no shade. Hey, life's a beach and stop complaining. You're just the driver and snack lady. Also, needs twice as many seats and trash cans. How about some picnic tables under the shady tree. At many splash pads closer to Boston, I've seen purgolas and canopies for shade...and few little trees can have huge potential later on.
Just go. It's a blast.