I would get a private guide/tour of the Vatican. There is one early in the a.m. and another a 7:30 or so. You'll need to google it. As to Naples we asked our guide to take us to his favorite pizza place. His favorite was closed but his second favorite was L'Antica Pizzeria da Michele where Julia Roberts was seen in Eat, Pray, Love. Gosh that pizza was good. Very laid back place with lots of locals surprisingly. We were the only English speaking customers.