It was rare to meet other native English speakers, so I'd be surprised if there were books in English. But if you are ok with French, search for
Compostelle, recettes du chemin by Anne-Marie Minvielle. It divides the route from Le Puy to Compostelle into 25 "grand stages," and offers two recipes from each. Here's a
review (in French).
With that, I suspect a recipe book would be better for nostalgia than for actually recreating recipes. My experience was that the food was excellent, but always based on very local and fresh ingredients. Dishes like
confit de canard was common and affordable along one stretch, but would be very $$$ to recreate in the US. A simple dish like sausage & lentils wouldn't taste the same using American supermarket sausages and lentils. And a lot of the best dishes I had were made right on the farm - violet and vervain syrups, terrines from wild game, soft cheeses, wild berry tarts, this walnut liqueur they added to red wine, a even the Armagnac. I wouldn't even know where to source them.
Side note: I don't have the book, I've only read reviews. If I ever find an affordable copy I'd grab it!