A friend of mine with young children was lucky enough to get away with just his wife for a few days. He was concerned about what would happen if their was an accident while he was gone. How would his mother-in-law be able to make medical decisions for his children if he and his wife couldn't be reached?
I was able to help him with a document that appointed his mother-in-law as a temporary guardian. For the duration of my friend's trip, his mother-in-law had the authority to make medical decisions for his children.
If your summer plans involve leaving the kids at home, consider preparing a power of attorney that specifically covers your time away.