Put all batteries in devices prior to camp. Place extra batteries in a large ziplock bag with a note on the outside labeling what batteries are for which item (i.e. Fan: D, handheld fan: AAA, etc.).
Practice putting batteries in things with your kids if they've never done it before.
Stationery
It is always a good idea to create address labels and prestamp and address envelopes for your children in advance to not only make it easier for them, but to make sure their letters actually get to the right place. Print address labels with addresses of loved ones and friends as well as return address labels with your child’s camp address.
Purchase a 10.5"x5.5" accordion file and designate a section for each individual’s address. In the last section, include extra labels and stamps in case they run out.
On the outside of the file, stick one label of each of the addresses, which will serve as an easy address book.
If you have a stationery clipboard, organize it so there are pens, stationery, and just enough envelopes to write home. You do not have to include every envelope that was provided with the stationery. Remember, you preaddressed them in the accordion file.