Thanks for all of the advice! I will forward it to my friends and I'm sure it will make for a wonderful trip. I have great memories of our 2006 trip to Normandy, in particular our stay at La Ferme du Pressoir, close to Bayeux (http://www.bandbnormandie.com/).

I've done the train to Caen, rented car and Peace Museum on arrival day twice, once in 2011 with our niece and nephew, and again in 2016 with friends. We did the RER to St. Lazare in 2011. We cabbed it in 2016. I recommend the cab. If you're friends are coming from JFK, they have a better chance of catching an early arriving flight. They may be able to catch the earlier train than the 12:10. (we almost took a flight connecting thru JFK that arrived shortly after 6:30) Both times we caught the 12:10 train, arrived at 2:00, and were in the museum before 3:00.

We always stay in Port en Bessin on the coast (7km from Bayeyux) and drive there from the museum. We've never had problems with jet lag, especially taking the train to keep in the sunlight.

To each their own.