The Boys and Girls club here is also open all day on schools out days. We did a mixture. Now they are teens we mix camps with staying home for "down time"
I have a story very similar to yours. Pulled my youngest from the school his older siblings attended for much the same reasons you are and we had a spot at a magnet school. We did our best to keep he and his best friend together as they...
Our Parks and Rec system has their own farm and does something like this and the town south of us contracts with one. A couple of our local CSAs also invite volunteer farmers.
We have found that our dancers and gymnasts of either gender pay more attention to their parents than they do to the instructor if parents are in the room. Both rooms are built without spectator seating because as a rec center we don't...
I work at a rec center and I share an office with the coordinator of Children's classes. We DO enforce our no siblings, no parents in dance/ gymnastic classes except for the last day, etc and you would be amazed how much flak we get....
We've done the second, but doing a search, I found the first http://www.kidsbowlfree.com/state.php?state=MT , https://freebowling.amf.com/
If you have a Cinemark Theater...
My son's Chiro does his sports physical ;-). He does have a regular physical with a male led about every other year, but way more expensive if he hasn't seen him already that year.