Pizza hut has, off and on throughout the years, had cross-contamination warnings listed for their pizza sauces-- for both nuts and shellfish. 

Clearly, they mean it.     Sorry about your DD's reaction.  I'd guess that you'd need to have her check in with a manager anywhere they stop-- she'll need to have some way to choose the "safest" of the options available to her.  Yes, McD's is probably the BEST option, but in some small towns, I know, you may simply not have a lot of choices.

Does your DD know how to cobble together calories from a vending machine?  If not, that's a skill I'd work on.  My DD can do that, and it's a good thing, because sometimes it's the only safe thing.

A convenience store can usually be a source for a single serving container of milk or juice, a cheese stick, a bag of safe chips, and/or a piece of whole fruit that can be washed and eaten.  That would probably be preferable to the risk at Subway or Pizza Hut. 

My DD14 was diagnosed with a peanut allergy this past summer, she has also been advised to avoid tree nuts because when she tried cashew butter it gave her a stomach ache. She is traveling with school teams, cheer/volleyball last season and this season Speech and Drama. We live in Montana and so they travel at least 100 miles to each meet! Therefore, they spend the night often and they eat at restaurants. We do have a 504 plan in place but it doesn't cover restaurant eating, I'm under the impression now that her 504 is not adequate but I'm not really sure what needs to go into it yet. She has done okay so far until last Saturday, they stopped at Pizza Hut for dinner on the way home and when she got home she had hives from her chin to her chest, she did not have any other symptoms so I treated her with benadryl and she was fine. In emailing back and forth with the coach (who had seemed so far to be understanding and accommodating)she said they stop at Subway, Pizza Hut and McDonalds quite often. I've read quite a bit and my understanding is McD is safe except peanut/nut topping on ice cream, flurries and any salads that have a nut topping (which are usually in a sealed packet, so easily avoided.). Subway bakes their bread on the same pans as their peanut butter cookies and can't guarantee that they have been cleaned sufficiently. So Subway bread is out. Pizza Hut has many items that are cross contact with peanuts/tree nuts, so I would like to avoid but it may not be possible for her on the bus. Is there any items at Subway or Pizza Hut that are not at risk for cross contact?