im not sure how you want to budget your time, as i spent more than two weeks just in italy but when i was in italy (with wife and baby) i flew in to rome, took the train down to naples, flew from there to venice, took the train to florence and flew from florence back to israel via rome. as far as france, on a different trip i flew from london to nice, rented a car while i was in the south, then flew from nice to paris. (im not sure it was necessary to fly from nice to paris though)