Actually…a teen would be a “mothers helper” and they are terrific. You are still there, but they really keep a watchful eye on the kidlets, maybe take them outdoors.
One thing to consider…and it relates to the arts and crafts project. Many kids at this age like to do things on their own time. It might be nice to have a craft box…glue, scissors, paper, etc…all the fixings for creative endeavors…that your kids could use as they choose. They get plenty of directed activities at school!
What about cub scouts or some similar thing?