Father/son Trip - 60th Bday

Can't help you with that, but if WWII buff, in London be sure to see American Chapel in the back of St. Paul's dedicated to US servicemen who were stationed in England and died during the war. Very impressive.

I can not comment on the ferry portion of your question, but I did go to Caen and Normandy with my father, who is a WW2 buff also. To go to the Caen WWII museum, Port Winston, the US Cemetary, Normandy beaches, and Pont du Hoc, you will need a full day or more. Depending on the arrival of the ferry in the morning, you might be rushed. Also, we had a car and could go at our own pace. Not sure how you would do it without a car unless you took a guided van tour. Good luck!!

Dan, I have to say one long day might be rushed. You can't just go to Omaha Beach and the American Cemetery, you have to walk it and ponder it. Let it sink in. When you look at the cliffs, the Allies are braver than you can possibly imagine. Rick has a section on planning a visit in his France book. I rented a car and explored the area. There are multiple museums as well as the sites. We went to Arromanches just because it's part of the story, too. If you find you have too much time, you could always go to Bayeux or Honfleur.
In London, don't miss the Churchill War Rooms- very interesting.

Dan, It's great that you're able to take a trip like that with your Father. I wish I could have done something like that with mine. Travelling from London, the most "time/cost efficient route" would be to travel by EuroStar to Gare du Nord, then to Gare St. Lazare and by train to Bayeux. The trip will take at least six hours, so plan accordingly. The D-Day sites are spread out, so difficult to reach them without a car. My suggestion would be to use Bayeux as a home base, and then take one of the excellent local tours. I can provide suggestions if you need them. There's also an excellent WW-II Musuem in Bayeux and of course the famous Tapestry which describes a much earlier battle. Among the sites you may want to visit there are Omaha and Utah beaches, Point du Hoc, the town of St. Mere Eglise and of course the American Cemetery. Just standing there is a very moving experience! If you're interested, look for the markers for two of the Niland brothers, who were part of the inspiration for the movie Saving Pvt. Ryan. You could also visit some of the locations made famous by Band of Brothers, depending on time. One very moving place (if you have time) is the small crossroads at Angoville au Plain, where two Medics from the 101st performed exemplary service in a small Church. It's a very interesting story! If you also wanted to visit the large Museum in Caen, that's easily accessible from Bayeux by train. As your Dad is a WW-II buff, I would highly recommend allowing at least two days in Bayeux, as there's LOTS to see. In London be sure to visit the Cabinet War Rooms, Imperial War Museum, HMS Belfast (moored on the Thames) and IWM Duxford Airfield (if time permits). There's LOTS to see in that area! Happy travels!

Don't miss Point du Hoc... I'm not sure if anyone else covered this in their reply, but if you want to tour the region (which is quite large), you will need to either join a guided tour or rent a car.

Dan,
Sounds like a special time w/ your dad. Good on ya! I was in Normandy last month. I would really encourage you to give yourself 2 days there to soak it in, particularly as dad is a WWII buff.