We are heading to Story land, but looking for other ideas as we are there 4 days.
Retaraunts, water parks ANYTHING-we have 5 toddlers 2-4age
If you have time before you, pick up a NH Breathe Booklet. They cost $30 but then you can get one child in free with an adult paying regular price. If you go to Story Land you've already paid for the booklet! Keep in mind that the 2 year old will get in free to most places but you'll have to pay for 3 and older.
The Conway Scenic Railroad has a 55 minute ride that is great for that age.
Right in front of the rail road station is a huge green lawn and playground if you need some run around time. There are some typical chain restaurants like McDonald's, Dairy Queen, and Friendly's and lots of independent restaurants. If you go to the Settlers Green Outlets there's a yummy pizza place called Brandli's in the outlets with a playground right outside (kids can play while you wait for your food to be ready).
There is an indoor water park in one of the hotels but I've never been there so I can't comment.
I agree with the previous poster - there are some nice, short, easy hikes to do with kids but it's best to have one adult per child because of the water.
Cranmore Mountain and Attitash Mountain both have summer activities but your kids might be a bit too young to make the price worth it.