If you live in the area..... many, many people around there have canoes that they hardly ever use. If you don't have one of your own, make friends with them!!
My grandmother used to live there and she would drive us grandkids several miles into the forest and drop us off with a canoe. Great times! Especially if the fish were spawning. We would jump out of the canoes trying to catch them. Pick berries along the shore. Cook the fish we did catch for our lunch along the shore. Great times!!! As long as the older two are responsible, I wouldn't hesitate to let all three of them go by themselves (provided they have experience with canoes and water).
Can you still volunteer with the Ramsdell theatre?
Make note of all the county fairs in your area. Are the kids involved in 4H? I highly recommend it if not.