No shoes allowed in the camper. I have a big rug I keep right outside the door. At night we put all the shoes in a big waterproof bag.
If you have a site with electric, bring a crock pot. You can set up your meal in the morning and after being out playing all day, you can come back to the site for a hot meal.
I pack my meats when they are frozen. They help keep the other foods cold, and they will gradually thaw in a day or two.
I like to pack most of the food in plastic storage containers. As I use the food, I have the containers that can be used for leftovers.
If you have a campfire, wrap up some potatoes in heavy duty aluminum foil. You can use them the next morning for hash browns, or heat them back up as part of dinner.
I always have 2 tablecloths to use for the seats at the picnic table. Most mornings the seats can be damp.
I have a small shoe boxed sized container full of card and dice games for rainy days. These games stay exclusively in the camper, so it's something different than what we do when were at home.
Beach balls make great toys. Don't take up much space. You can use them to play volleyball or even kick ball.
Have fun camping!