It will still be chilly. We did the Maid of the Mist in Niagara Falls this summer and found it spectacular. Your biggest problem might be finding campgrounds open that early. Have fun!
Pie irons. You can make pizza pies, apple (any fruit) pies, breakfast sandwiches and much more. You can use this for meals or snacks. Craft projects. Books about trees and bugs. Sometimes just sitting around the fire make up a story one word/person ...
We have been to Jellystone in western Ny a couple of times and had a great time. Fun for the kids and well run. When quiet hour came it was like someone flipped a switch, everything was quiet.