One last question regarding travel in Normandy in October

It is generally cheaper to pre-arrange rental cars. They have you over a barrel if you just show up needing a car. I don't think the car rental places are open on Sunday in Caen. If I were you I would probably train to Bayeux, do a beach tour from there and then pick up a car for the rest of the trip. Or train to Caen and pick up the car Monday morning. Maybe there is a rental open but I doubt it. In any case be very sure you will actually be able to get a car; for Sunday rentals, usually you are pretty much stuck with pick ups at major airports.

I would also reserve places to stay. We were in Honfleur, Bayeux and Mont St. Michel in late October a few years ago and the hotels we used in both Bayeux and Honfleur were both completely full. In fact our Honfleur B&B had made an error in booking and ended up putting us in their apartment although they gave us the B&B rate and included breakfast since we didn't want to cook for such a short stop. Here are snapshots of our trip:
https://janettravels.wordpress.com/category/normandy/
This is such a wonderful part of France. Hope you can work out the car situation. Try to include Etretat if you are going as far as Honfleur.

Jane, thanks for your help regarding the car rental. Just wondering still that to rent a car in Bayeux, it sounds very sketchy from previous posts, that the rental place is small, hard to find and not always open. So, I wonder if renting in Bayeux is an Option or stick with renting in Caens. Either way, I think we will travel on Saturday to ensure that the agency would be open.

The "agency" in Bayeux is actually a gas station, and was open around 6pm on Sunday a couple of weeks ago when we returned our car. We were scheduled to return it on Monday morning, but would have been pushing our luck to do that and get on our train on time, so we took the chance to take it on Sunday evening. The fellow there was renting to someone else when we showed up, then took ours back with no problem. He didn't speak English much, but we got by with little difficulty. It's on the edge of town, but we walked back to our rental right off the main pedestrian street in about 20 minutes or so.
If you rent in Bayeux, you should pre-book it. The place is really small and they might not have a car if you just show up.

I'd book in Caen, the agencies are right next to the train station. Just be sure they are open when you need them. I can't vouch for Saturday and they are closed Sunday They also close for a long lunch so be sure you know the hours they are open. We returned our car at 1:30 to catch a train to Paris and had to dump it in a lot and throw the keys in a slot and not get a receipt. At least in Caen they have lots of cars so pre-arrange and then be sure of the timing. Get the train tickets from Paris if that is where you are coming from 3 mos in advance and save a bundle.

We booked a car from Auto Europe to be picked up at the train station in Caen. Instead of a manual sedan we ended up with a Mercedes van that was automatic!! The whole operation was very casually run!! The small towns in Normandy are beautiful. We used Deauville as our base.

Re B&Bs -- the hotel we booked in late October in Bayeux (the Churchill) was sold out the nights were were there as was the B&B we booked in Honfleur. In fact the owner had made a booking error and didn't have a B&B room for us and so put us in the more expensive apartment for the two nights we were there; they billed it as B&B and we had breakfast (great breakfast) rather than cooking in our little kitchen. So I think that I would probably book ahead if you care about cost and quality. You will surely find something on the road but looking for rooms can suck up a lot of time, you'd rather be touring.