We did a sort of similar trip to Normandy. Rented at CDG and headed to Rouen for the night--not too far for jet lag. YOu could just go on to Bayeux, for example, for a first base. I would think you'd want to be in that area for a few days and then move on to Brittany. Doing the Loire also in that time frame might be a bit--certainly possible. I'll leave the days to others.
I will say you can return the car to Orly pretty easily and taxi into Paris.
If this is your second visit to Paris, I might wonder if you have seen "everything", although the markets, food and culture are very much always in our minds also.
The Normandy coast also has great seafood--have lunch (mussels!!) on the quayside at Arromanches after seeing the museum/display there.

Gretchen, you are very helpful. Previously someone mentioned to us to drop the car at Orly as that is easy.

Are you saying that when we are in Normandy, station ourselves there for 2 days and then 2 days in Brittany and 2 days in Loire Valley. Does that make sense?

Two days is a very short period of time in any of those three destinations outside Paris, but of course if that's all you have, you can work with that. I would base yourself in Amboise for the Loire (eastern end only - you don't have time to explore the west), Bayeux for Normandy (and be sure to see the Mémorial in Caen, which will take a half a day, then the beaches and Arromanches and the American cemetery), and Vannes, if you can get that far, for Brittany. Drop the car in Chartres on the way back to Paris; visit the cathedral and hop on the train. I don't see any benefit to driving all the way back to an airport.

It's a whirlwind approach, but I guess you work with the time you've got.I would personally choose Paris and one other destination, not three. Each of the locations you're planning to visit could easily consume a week.

St. Cirq, we have 10 nights in total. If 5 nights are Paris and we spent 5 nights in the Loire Valley (as you say and we agree - this is a whirlwind), then would you recommend to stay the 5 nights in Amboise? Or what? Thanks again.

No, I wouldn't spend 5 nights in Amboise. I'd first decide which of the three areas interests you the most. If the Loire, then I'd spend 2 nights in Amboise to explore the eastern end and 2-3 nights in Saumur or Angers for the western end. If Normandy, I'd spend 3 nights in Bayeux as a base for visiting the D-Day sights and 2 nights in Honfleur just because it's beautiful and you can see Deauville, Trouville, etc. from there. If Brittany, I'd spend 2 nights around Fougères or Vitré and the rest around Vannes.

We saw Versailles on the last trip, St Cirq. It was beautiful. So your comments are making us think more about going to either Normandy or Brittany. If we have 5 nights, is it better to stay in one of those two areas for 2/3 nights at two places? It sounds like doing both is "pushing it". Then to decide which one is best. I know what you are saying about winding roads. I am trying to do the one that provides the least windy roads if that makes sense. Thank you so much.

For eastern Brittany, you might be interested in my trip report from 2009:

http://www.fodors.com/community/europe/trip-report-france-summer-2009.cfm

For western Brittany and Normandy, you might want to look up my trip report that starts in Ghent; click on my name to find it.

You are honing in on it. St. cirq has said what I hinted at--I would go to Normandy for the 5 days and actually "see" it. We drove back to Orly ('cause I couldn't figure out how to return in Chartres!) via Chartres and had a lovely day there before going to Paris.

If Brittany, you could take the TGV to Rennes and rent a car there. Base in or around Dinan and explore that area. Here's a report I wrote about spending 5 days exploring in that area:

http://tinyurl.com/82azcyh

You could easily spend 5 days exploring this area but if you wanted to spend a few days around Vannes in The Gulf of Morbihan I've got a report about exploring that area:

http://tinyurl.com/8xuuryc

Any of the areas you're interested in will be fine so the choice is up to you. If you've already seen Paris in detail you could consider taking a few days off Paris and add them to your countryside excursion.

All of you are extremely helpful. You all make. Excellent points. Thank you.

We have now booked the trip. We have 4 nights in Normandy before we go to spend 5 nights in Paris. St. Cirq, you mentioned stay two nights in Bayeaux and 2 in Honfleur. Drop the car off at Chartres. Any suggestions? Does that make sense? Any suggestions for B&Bs in those locations? Restaurants? I really appreciate you guys on this board. everyone is always so helpful. Have a good day.

Do not miss Le Petite Bistro in Bayeux--make reservations. If you want some place cheap, squeaky clean, pleasant, large rooms try the Hotel Bayeux--5 minutes walk from teh tapestry, near the cathedral, easy access to the highways out of town.

You might want to check out the Hôtel L'Ecrin in Honfleur (there's also a B&B there that gets rave reviews here on Fodors but I can't remember the name of it - maybe someone else will). On our last trip to Bayeux we stayed at the Château de la Bellefontaine, just barely outside town (5 minute walk to center) and loved it. Dropping the car off in Chartres sounds like a great idea. And another recommendation for Le Petit Bistro in Bayeux.

great ideas here - bmking

Definitely don't miss Le Petit Bistro. We liked the Hoteo D'Argouges - everything in Bayeux is pretty close. It's a small and charming town. We also enjoyed dinner at Le Petit Normande, more informal than Le Petit Bistro but delicious nontheless.

I may be nit picking, but Le Petit Bistro is not a stuffy or formal place at all--a mom 'n pop's restaurant with almost no tourists when we were there. I just don't want anyone to think this is anything but wonderful food--the best meal we ate on the 2 week trip when we went. And we ate at Normande also. good but for the choice, it would be the bistro.