We are planning to rent a car in Paris and drive to Milan. Any advice and/or tips would be appreciated.
Just to connect cities, train or plane are faster. See www.viamichelin.com to help plan driving time and highway tolls. Travel by the fastest highways will rack up €150-175 in tolls. There is a hefty fee to pick up a car in one country and drop it in another, so if you are driving in order to reach some smaller towns, then consider a drop point inside the French border, such as at Nice or Modane.