I'll be changing planes at Charles de Gaulle airport and I will have 6 hours in between the flights. Is this enough time to travel by RER B line to Notre Dame, walk through the Louvre, Champs Elysees, Eiffel Tower, Champ de Mars and then get on the metro at the Eiffer Tower to Notre Dame and change trains to RER B to Charles de Gaulle?
1. Do I need to buy a RER B ticket and a metro ticket separately?
2. Am I crazy trying to do that in about 6 hours? (2 hours for travelling from/to the airport, 3 hours for the walk and 1 hour extra for the unexpected)?