Car rental (Rouen train sta.) return @ Pontoise or CDG airport.

I think you will be hard-pressed to cover all that ground even with a car. You could take the train directly to Bayeux and take a tour to the beaches, but I think you'd need a car to squeeze in the Loire. I doubt you'd have time to spare for Rouen though. Backbone is not the issue, rather it's what do you want to do in the time you have?

New to this, so pardon my not being clearer. Thank you for helping me to see I was trying to squeeze in too much! Plan is/was to just rent the car in Rouen and drive to Normandy and stay there 2 nights and then head to Amboise area (day/night/day). New thought is on evening of 2nd day will train to Paris and stay close to Gare du Nord for easy access next am for flight to Corsica. Sadly, Auvers-sur-Oise will have to wait for our next trip!

What Adam said. You're a couple of days short of being able to pull it off. Also, you've got things out of order - - you need to catch Auvers-Sur-Oise enroute to Rouen and then just continue on in one big circle - - Rouen, Bayeux/Caen, Blois, and then back to Paris. Accept that, hotel-to-cathedral, I can beat the train from Paris to Rouen any day of the week, thus you should get the car in Paris, especially since you'd have a stop enroute. We'll go from there. You're looking, along your route (not the freeways), at about five hours of driving to Bayeux. You need a couple hours in Rouen and probably that much in Auvers. That's a long, mean day. If you have to go get a car the departure morning, it only makes it worse. You said you wanted two days around the beaches. Okay. Having no idea of which chateaux ring your bell, Blois is four hours from Bayeux. Figure a couple of hours per chateau (?) and assume they're all right next to each other in a row. That's another sucko day and the last chateau will probably be closed by the time you get to it. Blois back into Paris is a couple of hours, easy. You don't add more than thirty minutes of driving time if you swing up through Chartres to see the world's best notre dame style cathedral. The driving is a piece of cake. Most of the stuff that makes the Wall is bad experiences - - people do it with no problems all the time. EDIT: Based on that we were both typing at the same time, you still can't do it. Cutting out Auvers only saved maybe three hours on the first day. Which you'll unsave if you take the train to Rouen. Even if you drive the whole way, it still won't work on the chateau day. If it makes any difference, there are places to turn in the car at Nord and access from the peripherique is stratight-forward.

RE-EDIT: Don't drop the car in town. Take it to the airport and spend the night there if you have a morning flight to somewhere.

Adam and Ed- thank you so much for your help and keeping me from biting off more than we can do! NEWEST plan: Day 1: Train from Paris to Caen (just under 2 hours). Rent car and do visit beaches. Day 2: More of D-day beaches. Day 3: Head to Cheverny (about 4 hours). Make it in time to tour and see dog feeding at 17:00. Overnight in/near Amboise. Day 4: Chenonceau 9-12pm. Lunch/Drive to Chartres (about 2.5 hours). Drop car in Chartres and train to Paris same night- stay at hotel close to Gare du Nord/CDG.
Day 5: arrive airport 10:30 for 12:30pm flight. You can probably see a running theme of avoiding a car drop-off in Paris!! Would not like to drive into Paris at night or morning of flight. Thanks for indulging my revised plans! -Anita

That'll work. Paris by night ain't a lot of fun since it's hard to see the street signs. Similarly, Roissy at night can also be a bear if you don't have some idea of the basic flow pattern. Have at it.

Yes, I think that its feasible and fun. I like the idea of ending at Chartres, I hope that is some compensation for the other great places you will no doubt get to see on your next trip.