OP had an original thread in the dining forum that explained more details about her dietary issue and a reply in that thread referred her here. OP, you might find it helpful to copy and paste that post so that those here can know exactly what it is that you need, and might be able to make recommendations.
I forgot, in my other thread, to suggest the fruit plate at Flame Tree at the Animal Kingdom. It comes with a side of yogurt (which I'm sure has added sugar in it,) but it's a very small (1/4 cup or less) side in a separately sealed container. It is a HUGE plate of fruit and I was quite satisified when I finished!
You might consider checking out the vegetarian/vegan thread in the restaurant forum, too -- I know that's not necessarily a facet of clean eating but there are lots of recommendations there that might help you find more basic, and therefore clean, foods. You're not going to find a lot of whole grain or unprocessed meat in the parks, so you might do well sticking to a primarily veg diet while in the parks and then picking up some protein on the way home. Or, you could carry snack baggies of nuts etc around... I went an entire day at Universal eating only what I had carried in my small purse-sized backpack (trail mix and fruit leathers, essentially,) so it is definitely do-able.
The "allergy book" at counter service restaurants won't give you nutritional information in many cases but WILL give you a complete list of ingredients, which should be helpful in determining if there are added sugars in the meals you're considering.
Also, to whomever asked about the soup -- I know Le Cellier makes their cheese soup from scratch, by the vat. Obviously that's not helpful to the OP but it is does corroborate that a number of the soups are not necessarily 'tinned.' Some may be, but some are not. I can't resist putting this emoticon, intended for a laugh...