Some people take a week or more to visit the museums and coastal towns of Normandy. We did it in a day trip from Paris, with a 3 hour drive each way to get there. But we were able to see most of what we wanted to see. For anyone interested in a short synopsis of the logistic issues that the Allies overcame when planning the invasion, see this website: http://www.usmm.org/felknordday.html
We started at the Memorial de Caen, which was originally a WWII museum, but has since morphed into also covering the Cold War, 9/11, etc. We then went to Juno Beach, where the Canadian forces came ashore for the Normandy Invasion on June 6, 1944.
We drove for about 30 miles down the coast through the little French beach towns, and ended up at Omaha Beach and the American Cemetery. We stopped at several small museums along the way, and had a 'stand up' lunch of fresh quiche at a patisserie.
It was a very moving day--full of history and sadness for all the soldiers who died, all the French townspeople whose homes and lives were destroyed. But all this set in the beautiful French countryside, full of flowers and quaint little seaside towns.
When they kicked us out of the Cemetary at 5pm, we drove down onto the beach.
On the return drive, we were running late and starved, so we actually went to McDonalds. McDonalds is kind of a sacriledge here in France, but it does have its place when you're hungry and don't have 3 hours to enjoy a 3 course meal.
We hit heavy traffic going through Paris, and then found that the freeway back to our hotel was closed! We spent another hour driving around in circles (thankfully following the GPS) before we managed to get back on the freeway north of the blockage. It looked like they were just working on the road, but didn't have any 'detour' signs out. If we'd not had the GPS to help us figure out where we were, we'd still be out driving around!