Late night walks to coffee / ice cream / gelati (sp?) shops, gazing into each other's eyes and making conversation over lattes for at least 3 hours, finishing with sweet makeout sessions on your downstairs couch!
Going to the zoo could be fun, your favorite intimate little restaurants, or just take him sightseeing and make fun of all the other tourists together!
Just have some quality alone time!
Good luck you two! Have a happy holiday together!