September: Paris, Giverny, Normandy, Brittany 16 days Realistic?

Giverny is easier as a day trip from Paris, because it is quite cumbersome to (1) store luggage and (2) travel from Giverny/Vernon station to Caen and beyond, because Vernon is not on the line to Caen.
Car rental in Caen would make a lot of sense to tour Normandy (but still look into tours for WWII sights, otherwise a beach is just a beach) and Brittany, but save yourself the drive back to Paris and drop the car off in Rennes.
16 days seems very realistic to me, depending how deeply you want to explore Brittany.

I suggest getting the Michelin Green Guides for Brittany & Normandy (2 separate books). They list virtually every town a tourist might want to visit, and also have some suggested driving itineraries. Also request Stu's itinerary; see https://www.fodors.com/community/europe/normandy-and-brittany-stu-dudleys-updated-itinerary-1670294/ We used both of those planning our trip to Brittany and Normandy a few years ago.

You have a few more days in the area then we did. We'd like to go back some day, still plenty left to see. For the WWII sights I'd recommend a tour company for a full day tour instead of driving on your own. They really know the history, have maps and photos, etc. We went with Overlord tours and thought they did a great job.

Sixteen days is plenty for Normandy and Brittany, you could spend some of that time in Paris. Like others, I suggest a train to Caen, car rental, D-Day tour. Bayeux is a good base to stay a few days. You could overnight at Mont-St-Michel, then visit St-Malo and other Brittany locations that interest you. Train back from Rennes. You could spend time in Paris at both ends of your trip, or focus your Paris time at the beginning or the end. Unwise to get a car at CDG and drive after an overnight flight, and unwise to try to get to CDG from anywhere but Paris on the day of your homebound flight. Sounds like a fun trip.

TY all for the informative replies.

There are walking trails along the cliffs around Étretat. You can walk all the way to Vaucottes and a bit further Yport. Or go the opposite direction, stunning views. Nice places to see like Benouville and Vattetot-sur-Mere, more south of Étretat like La Place and Brunevalle. To get there a car is needed.

Nearby Giverny La Roche-Guyon is worth the detour.

You can stay in B&B’s and Gîtes-de-France is a good source for finding basic places with good value for the money. Select a region to stay and under filter guesthouse (chambre d’hôtes), prices starting from about €50, some are even cheaper.
https://www.gites-de-france.com/en

TY sounds right up my alley.

Actually there are walking trails everywhere along the coast. For the D-Day beaches you can go to places you can’t get there with a car, so many won’t visit but might be interesting.

The Seine is surprisingly scenic down stream from Paris, worth looking to my idea for places to walk too. I really enjoyed the magnificent view from Château Gaillard over the Seine Valley near Les Andelys. Maybe the tourist office can help you (no garantuee they speak English): https://www.ville-andelys.fr/office-tourisme/

You can cross the bay for going to Le Mont-Saint-Michel during low tide. But you have to do this with a guide as the rising water can be very dangerous. https://web.archive.org/web/20151029122308/http://www.ot-montsaintmichel.com/en/traverseesbaie.htm Stayed on the mainland a few years ago at Le Rayon de Soleil in Bas Courtils. Decent spacious rooms and good breakfast, for €39 an absolute bargain. If I remember well a group was prepairing for a walk from there through the bay, likely they can inform you too.

Normandy and Brittany are much discussed regions, you can use the above search tool for finding more.

We drove from Paris to Normandy and found a great B&B in Bocage country.

You did say the extent of your knowledge about the Normandy campaign. But I'm not certain you need the guided tour. I went without. Normandy is very welcoming of Americans and signage is good.

At the Military Cemetery is a fascinating museum and I'm not certain a tour bus will give you the time you might desire. We spent hours and my 19 year old daughter, no interest in WWII, was not hurrying me at all. That's how moved she was.

Omaha Beach itself is void of the anti-tank and other war relics. But from the Cemetery you can get a real appreciation of the valor those who stormed that beach.

Pont du Hoc is just a short drive away. Again, you may not want to be hurried.

At Arromanches you will see remnants of the Mulberrys.
St Lo and St Mare Eglise (sp) ... most was rebuilt after the total destruction wrought by Bradley's bombing campaign.

Still, a drive through Bocage country gives a self evident explanation of the difficulties faced by the Armies.

Bayeux ... you should see the tapestry. That itself is several hours.

Mont St Michel ... plan a day. Big regret is we didn't spend enough time. We didn't need a guide.

Shorter answer to your question ... it depends on how many days you stay in Paris.

Gritz
I am a solo traveler female
It was trip of a lifetime
I did this via auto rental Auto Europe at age 72
I stayed at a bb in Tourne for 3 nites ,rest up and toured the Giverny gardens I love not being on a tour with time schedule,. lovely outdoor restaurant there . Able to tour Monets home.
So much to see in this 20 mile circle. Little traffic with the D roads, I’ll save the surprises for you.
I stayed at a Gite near Normandy for 6 nites (45E)
Do not miss Bayeux easy to park and so much to see. Each day I traveled to a different WW11 site . Ste Eglise , Utah , Omaha , all have museum . At Omaha one is struck by the American cemetery overlooking the vast empty beaches of the historical D day. Another gift of travel solo and time . Staying at one place allows the gift of relaxation and a short drive to sites. Everyone was so wonderful and kind to me.
I went first 2 wks June. The sun sets at 0930 pm
I highly recommend an auto self drive once out of Charles de Gaulle easy with navigation!!

Very best
Gayle

TY GoWest and Gayle...

great info to add to my collection and will look into. TY again.