Managed Missions is the site we use for organizing participants and managing donations. It is a one-stop shop for mission groups. managedmissions.com
Atlas Travel Insurance was the best-priced travel medical insurance. https://quote.hccmis.com/AtlasTravel/Home
Volunteer Card is the best-priced travel medical insurance, and it is much easier to acquire than Atlas. Multitrip plans are available for additional cost savings.
You try to give one ball per school, so a dozen per city is fine. https://themissionball.org/