Things in case he would get a stomach virus. Happened to us when DS was four and we were not prepared. We needed tash bags, paper towels, extra PJs, underwear, clear drink and plain crackers. If you go winter and it's cold.... extra gloves. It was COLD one trip and somehow the same DS lost like 5 gloves. Toys to play in the room are important to us. We all need a little down time and when he was little, have a few things to play with gave me a little bit of down time too. One trip we got the fill the box MR Potato Head and fill yourself
lego container and he played with those a ton during the rest times. We also always took something for the bath tub. A couple toys or soap crayons or paint and he would play a bit while we got things r day for the next day