Travel question

If you take a day trip somewhere a few hrs from where you live and don’t breast feed do you bring a lot of bottles with you as much as you need for when your gone or do you bring 1 bottle and try to wash it in between feedings? We went to the beach last week and ended up taking 8 bottles all ready filled with water and ready to just put formula in but I’m curious What other people would do. Keep in mind the bathrooms are nasty at our beach and I wouldn’t feel right washing the bottles there or else I would take just 1 bottle and bottles of water