Check with the Camp Director on what they would like you to teach. I had one pop a vein once when I brought up STDs and contraception.
Otherwise, teach wellness, wellness, wellness. Teach hand hygiene, good housekeeping practices, salad bar rules, accident prevention, etc. Teach standard precautions. Make friends with dietary so you will be welcome in the kitchen. You can look out for poor practice while you are visiting. Also, if dietary loves you, they will make sure you get good chow. One summer, long ago, I was eating scraps at the end of long meal-time med passes. That was really bad for my morale. Then the kitchen adopted me, and the good hot food and company made a new man out of me.
Round every day, starting during orientation, and do environmental surveys. Rounding is also a great way to make friends. Both new and old nurses need all the friends they can get. Visit during rounds, but don't "hang out." Make suggestions, but only to decision makers.
It won't take long to figure out if the camp has a culture of wellness and safety. If it does not, try to gently lead them there. Good luck!