Only YOU will really know what you need after you've been camping the first time. It really does depend upon where and how you camp what you need.
Basically though, for the kids, whatever you do at home, do it in the camper too. Anything you use at home for the kids, bring it along in the camper. Just because you are in a camper, your life style is no different than in your stick-and-brick home.
The only thing you really NEED for the camper are those things to 1) make the camper sit level. 2) have an electrical supply. 3) have a water supply. 4) have a sewer-dump supply.
After this .... ABSOLUTELY everything else is for your own convenience or your personal likes or wants.
Whatever you do in your home, your camper is just an extension of your home. It really is THAT simple.