I used an insulated picnic backpack 😂 it was easy to use and not so big that I could fit everything and the kitchen sink in it. We usually carried : a change of clothes, diapers, wipes, some toys and bottles with us. Super convenient

Mine has a couple features I really like. There is a zip in the back for access to thing that are in the bottom and there is a wire in the top to hold the bag open wide rather then a traditional backpack.