<<I would start in Paris, a remarkable place, then go onto to southern France. If you rent a car, tour Provence, if not take train to Nice. Nice to Cinque Terre for a few days of small villages/hiking/beautiful scenery and then onto Venice to spend time in another one of the world's most spectacular cities. You could also stop off in Florence on the way to Venice and again Rent a car for the Tuscany part of the trip. I wouldn't spread myself too thin. Remember you can go back>>

I think the above is a great suggestion. However, whatever you decide, include Paris.

3) Venice
4) Paris
5) rail

<<Somebody on another thread said Venice is Disneyesque>.

That person has no soul.