Fire Island for one day with a toddler and a 1yr old

We might go to Fire Island on Sunday for the day. Has anyone done this before with two young kids? I have no idea what beach we are going to, all I know is that we are to meet at the Bayshore ferry for the 10am ferry ride and return on the 7/8 pm ferry.
I’m wondering about food for the baby. He is a yr old and isn’t 100% on solids yet. He still takes 4 bottles a day. I don’t think I can keep milk cool for so many hours in a cooler… Is there somewhere I can purchase milk from or should I bring the parmelat but then wouldn’t that be too warm since we will be out on the beach almost all day and it may spoil with the heat?
What is a must bring? Will there be somewhere for us to change or wash up before we leave? Will a City Mini double stroller work on the sand or should I just bring a wagon?
Any tips would be greatly appreciated.

Re: Fire Island for one day with a toddler and a 1yr old

I am assuming you are going to Ocean Beach because that is the town with the most going on.

As for the food. There are several markets there and they will have all the basics including milk. You probably want to bring baby food because everything on FI is really expensive.

There is a bathroom that you can get changed in at the western end of Ocean beach, but I am not sure about showers.

I have always brought a stroller because then my DS has somewhere to sleep/rest. You can leave it on the boardwalk while you are at the beach.

We also have a beach cart which we load up with cooler, chairs, umbrella, towels, beach toys.

In Ocean Beach you have to walk up and down stairs to get to the beach so its a bit of a struggle if your kids aren't walking yet.

There is also a playground and lots of restaurants so your kids will keep busy.

Fire Island for one day with a toddler and a 1yr old

Thanks so much for the suggestions. I planned on putting the baby in the bjorn or the stroller, and DS1 would walk/go in the wagon. I'm not taking the double as our friends kids are not in strollers anymore and once he sees the kids walking or in wagons he will refuse to be in a stroller. It just seems like a lot to bring for one day. But I guess that's what happens when you have kids. lol Thanks again.