My advice is to email the special diets team if your tirp is a ways off- they will email you a list of places and foods they feel are safe for the allergic person .
yes they have HUGE notebooks and it takes quite a few to look thru them.
What I do with my wheat/gluten allergy is print out the list they sent me, tuck it in my pack and when I go to counter services I pull out my list and SHOW the CM what I want. The CM will call a MGR who will come running with a notebook

I show the MGR what I want. I have never ordered at a CS and Not had a mgr come out
At table service places I try and let them know 72 hours in advance but we do a lot of day trips and sometimes call the night before for a reservation
most table services can fix you up with no problems if it a "Simple" Allergy-
(and I don't mean Simple as in easy

no allergies are easy- i just mean an allergy to wheat or milk or 1 item)
now if you are allergic to 25 different things or need a super special diet I would call way in advance.
We go to Disney A lot and i have never had a problem so far with food
Hope this helps someone
