You might want to make a note of a few easy ones with recent finds, in case they're struggling to find any. Make sure they all know the basics: If they take a swap item they should replace it with something of similar value. Travel bugs want to travel - they should only be taken if they're to be put in another cache. Rehide caches as you found them. And leave no traces you were there - easier said than done with a group of fourteen-year-olds, I know! I hope it all goes well - enjoy!
Do not go gentle into that good night.
Rage, rage against the dying of the light. (Dylan Thomas)