From the time you step out of Charles de Gaulle Airport in Paris, you could be in Normandy in less than 3 hours.
From the airport, take a taxi ride to the Gare Saint-Lazare train station. Or hop on an RER Line B train and take the 30-minute ride to the Paris Nord station. (The RER train will cost less.)
At Paris Nord, switch to a Line E train for a 5-minute ride to Gare Saint-Lazare.
At Gare Saint-Lazare, board one of the hourly regional trains to Caen/Bayeux. The ride is 1 hour and 45 minutes.
Upon arrival in Caen/Bayeux, take a taxi to your destination.