Bring a hammock - a place that's not your tent but is still yours
'Naked Time' - Make sure the kids dry off after paddling every day, send them off in different directions so they have 15-30 min alone before getting back together as a group, it also works as a self-reflection period.
Plenty of line to hang stuff up to dry
If your running the trip I think, you're campsite is on a lake that has a couple other streams and rivers draining into it. If your lucky we'll get rain just before the trip and some of the other rivers will be running, some of which are just canoe routes with quickwater, some which have some whitewater, and would be other places to work on skills without hiking.
Remember you can always pick and choose how far up a rapid you want to start, you can't pick and chose where you will be getting the kids out of the water.