We went to England in March/April this year to visit friends we met on our Med cruise two years ago. We took a ferry from Portsmouth to Caen and drove our rental car to Normandy for three days. Not that this answers your question about doing it as an add on or excursion, however.....
If you are in the area and/or have the ability to go, Normandy is not to be missed. We saw all 5 beaches, the American Cemetery & Museum and the British museum/cemetery (which is closer in town to Bayeux, which was a beautifully quaint little town). I can't say enough good things about how beautiful and peaceful Normandy is. Being there and seeing first hand what our soldiers had to endure on those shores, from those cliffs...will change your life. It certainly changed mine. You can also see the Mulberry Harbour, still intact pillboxes, etc.
One other thing that was endearing was to see how many little businesses and residences still fly the American flags. It's a sign of appreciation and respect, nothing else. Being in Normandy felt like I had stepped back in time. I hope to go back there some day as there are so many things we didn't have the time to see. Our three days there were my favorite part of that vacation, and that area of France is now actually my favorite place I've ever visited.
It's all incredibly moving and as someone else already said, bring tissues with you.
We stayed at the Ibis in Port en Bessin...a little fishing village about 10-15 minute drive from the American Cemetery. Very nice/clean hotel and walkable to many cafes/restaurants.
My 11 year old daughter is a history buff. In particular, she loves everything about the history of WWII. She looked so forward to Normandy and when we were there, was so immersed in everything. She had an appreciation for what she saw....and that can be hard for an adult to do, let alone a child.....
