Absolutely Truly by Heather Vogel Frederick

At almost six feet tall, twelve-year-oold Truly Lovejoy stands out in a crowd whether she likes it or not. (She doesn't.) So when her family up and moves to teeny-tiny, super boring Pumpkin Falls, New Hampshire, Truly doesn't stand a chance of blending in. But when helping out at the family bookstore one day, Truly finds a mysterious letter inside an old copy of Charlotte's Web and soon she and her new friends are swept up in a madcap treasure hunt around town. While chasing clues that could spell danger, Truly discovers there's more to Pumpkin Falls than meets the eye- and that blending in can be overrated.