Day 6 - rent car and drive to omaha/dday beach - 3 hours drive. Leave by 8 am. Spend day touring memorials. Drive to Mont st Michel in the evening - 2 hours

Impossible day - stay in Bayeux and drive leisurely to beachheads. Bayeux is a neat city itself - famous cathedral and Queen Matilhda's famous Tapestry documenting Norman conquest of England in 1066.

Then spend leisurely day driving to Mont Saint Michel and stay there.

Yes taking train Paris to Caen and renting car may be quicker as getting out of Paris area itself could take time - booking in advance can yield rather small discounts (unlike TGV trains) so you could just show up at station and buy tickets that day rather than being pegged to a specific unchangeable train long in advance like discounted ticketing would require. for lots on trains check www.seat61.com - a cornucopia of sage advice on discount train tickets; general info and also for driving routes - www.ricksteves.com and www.budgeteuropetravel.com.

Suggest Amboise as your Loire base and easy drive to Chenonceau from there and Amboise has own great castle too and in summer there is a neat Sound-and-Light Show in castle grounds with English headphones - a spectacle as French would say.

Amboise also has the compelling Clos de Luce (sp?) -Leonardo da Vinci's old estate he spent his final years in after being enticed here by Francois 1er (?) to symbolize coming of Renaissance to France - copies of many of his discoveries are on display - right near chateau.

Next day on way out you could stop by Chambord - along with Chenonceau the most popular and famous Loire chateau.

I agree with others that you should slow down and savor various areas more than being on road most of days as planned. Yes drop Dijon as advised - head right to Chamonix.

Easy for novice tourist to think in American terms of dashing between pt A and B but in your itinerary there is so much to see that you will be blowing by on autobahns. the 2nd half of your itinerary is more realistic but the first week way too much IMO.

day 14 - day 16 : stay in Verdon Gorge and explore

don't stay in the gorge!

I did do a canoe thru the gorge and even in August just dropped by and rented our own. Tipped over once only!

Autoroutes are fast and easy and BORING - be sure to slow down and take some side roads too and see a whole different France - especially nice small towns and villages to stop in for a coffee or snack or noon meal at the local cafe.

But, less can indeed be more sometimes!

Why not stay in the gorge ? We did it several times.
Stopped when the sun set.