We took The Seine Paris to Normandy in late March/early April of this year. The day we went to the Normandy beach sites was about right for us, but we were both born after D-Day and had no family lost there. We left the ship in Honfleur right after breakfast, at 8:00 AM and returned at about 6:30, on time for dinner. They provided a so-so picnic lunch, so that we did not waste time having to have lunch. It was about an hours drive to the Peace Museum at Caen, where we picked up our guide, Bruno,. He was not that good, particularly at Pont du Hoc, as he let the group get strung out and lose the radio signal at times. He was the only guide on the whole trip that was not excellent. The other groups were happy with their guides. Time driving through Normandy is not wasted, as you get a feeling for the land and the small villages. The first stop was at Longue-sur-Mer where we could walk through German gun implacements as the were left after D-day. It was actually a raw windy day that helped with the feel of D-Day.
From there, we went to Arromanches where the allies had built a tempoary harbor to support the invasion. There were many remnants of the temporary harbor still there. and there was an excellent small museum there where we happened onto an English language presentation a a group of Canadian students on the activities in building and using the harbor. There was also a slide show and film clips. Most people skipped eating their lunch to make the most of this town.
From there, we went to the American Cemetary at Colleville-sur-Mer, where they had a ceremny for us, as visiting Americans, with each given a rose to place on a grave. If you have loved ones buried here. this is the one place that the timing is tight. Make sure that you have the grave location in advance, if you want to visit it.
Then it was on to Omaha beach, with time to visit the 2 memorials there and to appreciate the immensity of the beach.
The last stop was at Pont-du Hoc, where the rangers scaled to cliffs in the landing. The site is as it was left with craters and destroyed bunkers.
Then, after this very busy day, it was back to the ship.
Thre were 2 other partial days relating to the invasion. The last day of the main trip, we went back to the Peace Memorial in Caen to visit the museum for a couple of hours. It was quite moving and were learned much of the pre-invasion times.
On the Brittany extension, we also visited a German Osuary near Mont St Michel where many German remains are intereed. This was not on the planned itinierary, so I don't know if it would be repeated.
Unless there are other sites that you would want to visit or you would want extra times in these sites, I see no need for a separate trip.
I did a blog format trip report http://jackthetravelingman-seine,blogspot.com.
We would be glad to answer further questions, but we are traveling right now with spotty internet access, so the responses might not be as quick as we would like.
The Brittany post-trip extension was well worth it, showing us another time in history, St-Malo and Mont St Michel were spectacular.