I carry a regular size backpack, plus wear a fanny pack. The fanny pack contains MY stuff - sunglasses, chapstick, mini sunscreen, credit cards, license, money, camera and the like. The backpack contains everything for the kids - light jackets or sweatshirts, long pants if they're wearing shorts and the temps for the evening will be a lot lower, ponchos if the forecast calls for them, snacks, wipes, a towel, sunscreen, water bottles, bandaids, aspirin and stuff like that. Sometimes I feel like a pack mule, but we always use all that stuff, so it makes sense to me to carry it. I just take it on the rides with me and it's not a big deal.