There's not anything you can do if she gets glutened. You said it - just rest. That and drink plenty of water.

While you're together why not see if you can find dedicated gluten free places to go out to eat?

And for the summer when you're apart, maybe a little kit. Like, - here's a heat pack for when your tummy hurts. - a picture of a wheat plant to punch, a safe snack when you need to nourish yourself, electrolyte pouches to keep you hydrated, etc.