I would really like to carry my SLR camera in the parks. I am thinking of getting a small messenger or sling bag to carry that and a couple other things. Will I end up finding it to be more hassle to carry my camera than it's worth? I know there are some rides that will require me to use a locker (I probably wouldn't be going on every one of those whether I have a large camera or not), but would a bag that's bigger than a fanny pack but smaller than a backpack work for the majority of rides/attractions? And that reminds me- do I need cash or coins for the lockers, or can I swipe a credit card? Thank you!