LinkParis.com's Small Group D-Day Tour vs. The Big Bus Tours
US - Rail from Paris to Caen takes 2 hours.
BUS - The ride from Paris to Caen is 3 1/2 hours without traffic.
US - Linkparis.com tours have a maximum of 8 people per group with an English speaking guide that details places and things that are relevant to the Normandy beaches and invasion.
BUS - Tour buses from Paris can have up to 50 passengers. Commentary often given in different languages. Even if the commentary is in English it goes on and on and on....