but by no means is it anything but just my opinion.
Rome-- 4 days
Siena (Tuscany)-- 1 day
Florence-- 2-3 days
Venice-- 1 day
Milan-- 1-2 days
Lake Como-- 1 day
Amalfi coast-- 2 days
Pompei-- 1 day
If driving you can make a quick stop in Bologna or Verona.