D.M.
Hi J.---I applaud you for wanting to offer your children the opportunity for camps and a variety of other activities. I beg you to consider an alternative.
I believe that kids these days are WAY overscheduled. People need downtime, they need to learn to relax. Your kids are so little, they need their rest. I know you say that they won't sit still/put their feet up, but I think that maybe this might be your most important activity to teach them this summer. As someone else said, set up that schedule. When the new baby sleeps, everyone sits down for their rest. They don't have to sleep, but they definitely need to learn quiet time. Kids also need to learn how to keep themselves occupied without having to have you do that all of the time.
Go to an appliance store and ask for discarded refrigerator boxes. Bring them home and have the kids build playhouses and forts. Get a ton of sidewald chalk and let their inner artist shine. Go for walks in local parks. Have them see how quietly they can walk and how many different things that they can hear or see. Read, read, read. The new baby can benefit from being read to as well.
I wonder how many kids today are being diagnosed with ADHD because they never learned to sit still when they were little. I don't know, it's just a thought. I work with a Naturopath and she feels that many problems with kids today are because of lack of adequate sleep (electronic devices in bedrooms-they should be for sleep only) and overstimulation. Just my 2 cents worth. Good luck ! D.