This is never a problem for us b/c we charge everything to our room, then pay it off with gift cards several times before the end of our trip before they would charge our account. That way we get free gas by buying gift cards at Giant Eagle, and we have the ease of not having to carry cash around! I know that won't work for everyone, but we find it much easier as I am someone who hates carrying things around if I can help it.
This year we are instituting the carry your own stuff plan. We have always had a stroller with us to carry stuff around, and this will be our last year, so I want to start the kids getting used to carrying their own stuff. That way the load is split, and no one has to stop and dig through our gigantor backpack for moleskin. They will each have their own back sack that will have their own little care kit in it. Each bag will include: sunscreen, lanyards, pins, a thin change of clothes, chapstick with spf protection, sunglasses, moleskin, bandaids, camera, inhalers or whatever medication is needed, etc...
I know that is not exactly what we wished we had but didn't bring, but maybe it will give someone else some ideas. Who knows? Since I don't like to carry things, I use things on my person that I don't physically have to carry with my hands. I use a clear little zippy container that is on a retractable cord attached to a clip. It clips to my chest and holds KTTW cards, my ID, and fastpasses. I also gave in and bought a little hip pouch that holds my phone and various little things I may need. It is NOT a fanny pack. I swear. Not sure what I'm gonna do when we ditch our stroller for good b/c it carries my changes of shoes (which are necessary due to major foot injuries), my body glide, and my anti-monkey butt. I guess I could rent a locker...