Mrs. Nash's Ashes by Sarah Adler
Millicent is on a mission. When she promised her elderly best friend that she'd reunite her with the woman she fell in love with nearly eighty years ago, she didn't expect that would mean traveling to Key West with three tablespoons of Mrs. Nash's remains in her backpack. But Millie's determined to give her friend a symbolic happily ever after, and hopefully reassure herself of love's lasting power in the process.