I've got a camper but we mainly use as a day van.
Having 2 kids I've tried to get it to a place where when going out for the day we don't need to do a big pack beforehand.
In the van we have all the standard cooking stuff, bbq, plates, cups etc.
Toaster, kettle, air fryer.
Sunshade awning.
Backpack and water bottles.
Towels, beach stuff, change of clothes.
Outdoor games and balls.
Blankets and chairs.
Wet weather gear, wellies etc.
Drinks in the fridge, small amount of dried food.
Phone chargers, power banks.
Toilet, wet wipes, meds, first aid.
Internet and ipads.
Folding firepit.
Other random items, tools, jump pack, inflator, touch, BT speaker, jackery.
Seems a lot but as I say everything has it's place, tucked away and lives in the van. Don't think about it until I need something.