Next summer, wife, kids and I (4 of us) will be going to London, then Northern France (Normandy, Paris, Loire Valley). Ideally, I would like to include the Normandy and Loire Valley area. In London, we will be staying close (about 10 via Taxi) to the St Pancras area. I much prefer not to drive into Paris. Which two itinerary makes for a better trip:

Trip A)
Day 1 - Take Eurostar to Paris
Days 2 to 6: Paris area including Versailles
Day 7 to 9: Take train to Amboise, Loire Valley. Drive to St. Michel, Bayeux.
Day 10: Drop car off in Caen, Normandy, then train to Paris
Day 11: Fly back to US.

Trip B
Day 1 - As of now, it looks like Ryanair flies out of STN to TUF (Tours, France).
Days 2 to 5: Tour Amboise, drive to Mont St Michel, Bayeux (Normandy)
Day 6: Drop off car in Caen, then train to Paris
Days 7 to 10: Tour Paris
Day 11: Fly back to US

Trip A, it is easy to get to Paris. But then, I have to go to Paris twice. Trip B is harder to get to STN and it is flying Ryanair. But, I go to Paris only once. Any suggestion?