on our first trip to disney with our toddler we used a backpack. the stroller and it matched, and we hung the backpack over the handles. when we went on a ride, DH wore the backpack and then set it on his shoes when we were on the ride. it was easier than a diaper bag. i had used the diaper bag before when out with baby and the stroller at Sesame Place. the diaper bag had a single strap that kept falling off my shoulder, swinging around and bumping into everything in the stall. Gross! For Disney i knew we had to try something else. Jansport Big Student Backpack was perfect. the material is super thin and we actually packed it in our carry on bag at the airport, it laid super flat. There are a bunch of compartments, which made it so helpful and the largest compartment fit her potty, which she uses at home, the Bjorn compact potty, slides right in and out of the compartment, and it barely fit in the diaper bag. As far as zip tieing, i think something else would be a better option unless you are never planning on removing it. We left many things under the stroller, and our resort mugs tied with a fluorescent shoe lace to the cup holders, and it was never bothered with. We also saw many strollers just left as is, with the kids' drink in it, all their stuff it in, just took out the kid and went on the ride. One other thing that may work well is using clip, like a linking clip for baby toys, and let the bag hang from it. Good luck and have a good time! dont forget to pack the sunscreen