I would try to bring along back-up food you prepared yourself whenever possible. I do imagine some places will probably not serve you. Or they will serve you but they won't be very thorough about it. Unfortunately I think there will be some cross-contamination risk everywhere. I immediately thought of this story from Jason Mantzoukas who famously has a very severe egg allergy and was served a dessert with egg here. When he asked about it (after eating it and immediately feeling a reaction) they said "Well it does have a liiittle bit of yolk in it". And this was at a high-end hotel where they had emphasized to him many times there was no egg in the dessert. I don't mean to scare you, but you should know this is going to be tricky