These questions are best addressed to the actual hotel and not a general Google question. You can look at website of the hotel and explore. The beach is very close and you could walk to it or drive if you like. It's a lovely area. I believe you can bring a pet for a fee booked in advance. Not sure they could accommodate that at the last minute. There is a lovely formal dining room which with well behaved kids should not be a problem. It is very elegant. Not sure if kids activities of the hotel itself beyond there is a pool. My guess would be as parents you entertain your own children. Most hotels especially like this will have at a minimum babysitter services or recommendation is that would be your need. Taking your children to the local beach should be the best entertainment and it's lovely. I would imagine the hotel would have some beach needs such as chairs and umbrellas etc or pack a picnic for you if you would inquire. Ask the concierge or call and ask them in advance.
I've been to this area (Castle Island) many, many times. Plenty to do in the immediate area with 5-16 age kids. There is a beach less than 5 min away I think it's like $15 for the day for non residents and there is a nice pool on site the kids love. Also the Wentworth is Pet friendly at a fee. I believe its $50 extra per night per pet but you would have to verify that. Good luck!
Willis Sands beach is 8-10 min drive. Very nice and family friendly. Lots of kids in the indoor and outdoor pool, but no other activities otherwise
On my last stay, there didn't seem any family activities, nor did the hotel offer or advertise any upon arrival
You might want to click on to the hotel's actual website to get an answer to these questions. Sorry I don't know the answers.
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