White Van Man here! I've done the white van bit at Caen last year supporting a CTC tour from Caen to Cannes. This is what works well:
As mmmMartin has said, we'll cross on the day of the Friday. I plan to travel by train on the Thursday from Northampton to Euston and Waterloo to Portsmouth. I'll pedal on a light bike with thin tyres and no rack, and carry what I want to take in a rucksack. Three miles from my house to NMP station. Three miles (if that) from EUS to WAT. A mile (if that) from PMS to the
Travelodge.
On the Friday, a mile (if that) from Travelodge to Portsmouth ferry terminal. At Ouistreham, half-a-mile from the ferry through the terminal to the Hotel Normandie.
That worked well for me last August. So, at the start of our tour in June, that is all you would have to do. In fact, slightly shorter in Ouistreham as, on the Saturday morning, mmmMartin and I will meet you at the terminal gates with the van ready for your luggage.
[When mmmMartin and I cross to Ouistreham on the Friday, we will leave our luggage at the hotel and pedal in to Caen - 90% by a cycle path; put bikes in van and return to Ouistreham.]
On the Saturday at the end of our tour, many people will be getting the 1630 ferry from Ouistreham. We will meet you at Caen railway station, handing your bike to you there. mmmMartin and I will be dependent on the time that Europcar (or whoever) want the van back and/or when their Caen office closes and/or we need to get the van back before another 24 hours is added to the hire and/or how easy it will be to find a recycling centre for the disposal of the wood from the frame mmmMartin is going to erect in the van for the bikes. The car- and van-hire offices in Caen are in the Place de la Gare.
I don't think it's possible to get the bikes out at Caen Place de la Gare and put your luggage into the van and drive it to Ouistreham because of all those and/ors in the last para, although I'll defer to mmmMartin on this point.
mmmMartin and I have already decided that we will catch the overnight crossing, 2300 from Ouistreham, just in case there are people whose travel arrangements back from Bordeaux mean they get to Caen late.
Thus mmmMartin and I will be pedalling from Caen Place de la Gare to Ouistreham in the early evening. I'll be carrying what I've taken in a rucksack and that worked well - even in the rain - last September. Here's a record of my route:
http://ridewithgps.com/trips/2183754
and you'll see that, of the 9.8 miles only the first mile is on road and then it's cycle path alongside a canal. It is smooth, well surfaced with tarmac, and there are no gradients.
So, what I'm saying is that you could easily use a light bike without panniers and carry your stuff in a rucksack.