Ugh, diets on vacation...no fun!
I completely understand where you're coming from, tho. DH and I have lost over 70 pounds combined since last August on the Mediterranean Diet/American Heart Association Diet, and we didn't want to flush our hard work down the toilet...not to mention, we were a little concerned with how our tummies would react to high-fat/processed foods.
Definitely remember all the walking you're doing. This will allow for extra calories! DH and I also craved heavy protein from the extra physical exertion. Red meat is a once-a-month treat on our diets, but we ate it almost every day at WDW.
I can tell you the TS restaurants were very open and accomodating about how they prepare their meals. At PTC, I ordered the pasta primavera with grilled seafood, and I was told they only use 100 percent olive or canola oil in all their dishes. I was also pleasantly surprised to see partially-hydrogenated oils gone from all their snack foods you can buy in small bags at the shops (I follow the "good fat" diet, i.e., olive oil, nuts, avocado are okay in moderation).
Tusker House in AK has some very nice choices, grilled salmon and roasted half-chickens. I'm seeing more "health conscious" options every time I go to any of the parks/resorts.
Don't forget, too, you're on vacation. Eat a balanced, big, healthy breakfast if you can each day before hitting the parks and don't forget a one-a-day vitamin. My trainer told me, "It's not what we do 10 percent of the time that counts; it's what we do 90 percent of the time that counts." Make sure to treat yourself a little for all your hard work and tremendous walking!