Once we were on vacation in a resort town over spring break, and D1 had some report due the day she got back to school (assigned the Friday before they left, don't get me started...). Anyway, we went to the public library. While she was researching I found a book on the shelf by her favorite author in a favorite series that we had not known existed ("The River of Adventure" by Enid Blyton). HAD to have it to read. The library allowed us to pay a fee for an "out of town" library card. We checked out the book and mailed it back from home a couple of weeks later.
Worth every cent... Check the website for the public library where you are traveling, they might have a similar option.
And when I was a kid -- we just took shopping bags of books on every trip (but traveling by car, can't tell if you are).
