Northern France in 12 Days

One quick suggestion: Since you have to fly home from Paris, why not put all your visit at the end of the itinerary to save some back-tracking.
Of course you should be reading Steves' advice for Paris and elsewhere that is already available on this site.

Completely agree with Southam. Leave Paris till last so you can relax and enjoy a full day of sightseeing the day before your flight. It you do that you might not need to stay out at CDG--though that's a matter of personal tolerance for transportation risk and needing to get up earlier in the morning. I will say that I opted to stay at CDG the night before a flight (for reasons that don't matter here). The hotel was fine but didn't start serving dinner until 7 PM, in line with French cultural norms, however inconvenient that was for people with flights the next day who wanted to crash early. I was not pleased.

There are at least two rail departures each day that will get you from Basel to Bayeux in under 7 hours. However, there will be a station change in Paris (Gare de Lyon to Gare St-Lazare), which is annoying. I'm a senior female and have done that via Metro, encumbered by non-carry-on luggage, but not with as much baggage as you might have after a river cruise. Many people would suggest that you budget the time and $ for a taxi between the two stations.

There doesn't appear to be a way to save time by flying part of the way from Basel to Bayeux and connecting to a train.

If you're thinking it would be easier to go to Paris first, I imagine some others will agree with you. But I'd bite the bullet and leave Paris till the end. From my perspective it's a choice between some awkwardness on the day your cruise ends and losing a lot of sightseeing time on the day before you fly home.

Your transportation options by train from Basel to either Tours or Bayeux, as well as between Bayeux and Tours, are cumbersome. See Rome2 Rio https://www.rome2rio.com/ for the transportation options.

As much as the end-in-Paris itinerary would be nice, due to the poor options, I suggest you go directly to Paris for your visit, pick up a car on your way to Tours at Orly Airport, use the car to visit the Loire and drive to Normandy, and the night before your flight, drive to a CDG airport hotel, unload, and and then return your car. Orly-Tours and Bayeux-CDG are easy routes. Or, you could take a trains from Paris and back to Paris, if you don’t mind spending on both a car and train the same day.
We stayed at the near-empty CDG Hilton three weeks ago. No shuttles are running to the hotels and no one knows about after the crisis.

FYI-
Always check for French labor strikes. These can affect any public transportation: planes, trains, buses, etc. They are generally posted well in advance. Often other labor unions will strike in solidarity, and other businesses affected. For example, museums could be closed as the employees couldn't get to work.

We were caught in the big transportation strike Dec, 2019. I was totally ignorant , so never checked for any strikes. It was publicized six weeks in advance. Since the French seemed accustomed to these strikes, our hotel folks weren't really very helpful, just saying "it will all work out".

But wishing you good luck -and safe travels- and no strikes.

I am a self-admitted worrywart about being on time for flights, especially those that involve crossing the pond. Your return flight is at 11:25; therefore, I wouldn’t plan to be at CDG any later than 8:30. To me that says sleep at one of the hotels there. You can eat dinner before heading out to the airport, or eat your main meal midday.
The Sheraton is in T2. There are a number of others just outside of the terminus of the shuttle train. We once stayed at the Hilton and could have walked to the shuttle (5 - 10 minutes?), but opted for their shuttle bus. I don’t however recommend it. Our experience just wasn’t the best.
Departing from CDG is no simple matter. We had to wait in line to check in and to check our bags. After that, there was another line for getting our passports checked for Schengen rule conformity. We used up around 2 of the 3 hours we had allowed. Then, we were able to relax with some nice coffee and pastries.

When I plan a trip, I see what’s convenient instead of trying to plow through my bucket list. For example, Basel is 45 minutes from Colmar which is a beautiful place to spend a few days and you could work your way to Paris from there. For instance, you could spend time in Colmar before moving on to Strasbourg and from there take a direct train to Paris without having to connect.
Another thought is to fly nonstop on EasyJet from Basel to Nice and see the riviera and Monaco. From Nice you could work your way back to Paris by taking a direct train to Avignon and also explore the Provence area. From Avignon you can take a direct train to Paris. Both itineraries are easier than the one you have planned.

Since the only realistic way to get from Basel to Tours or Bayeux takes you through Paris, where you have to change stations, I can see the value in spending those days in Paris before you head farther west. If you visit Normandy first after Paris, and then head to the Loire, you could get a TGV train from St-Pierre-des-Corps, near Tours, direct to CDG the afternoon before your flight. It takes about 90 minutes and bypasses Paris. Then spend the last night at an airport hotel. The website many of us use for planning train travel shows this train leaving St-Pierre at 14:54 and arriving CDG at 16:42 on Oct. 13. St-Pierre is close enough to Tours that I'd think a taxi would get you there, or there could well be an easy bus service.

This website would be useful in planning and preparing for European rail travel. It doesn't show schedules but has lots of good info about trains.

Assuming you want to stick with the train, it seems like the connection between Bayeux and Tours is just going to awkward. You might want to consider stopping in Dijon on your way from Basel to Paris and using Dijon as a base to see Burgundy, then to Paris, then Tours and then return to CDG. Of course, this substitutes Dijon for Bayeux, which is not what you proposed.

On our visit to Bayeux/Normandy we had a rental car, and scheduled our own itinerary, with the Rick Steves guidebook a key resource. But there appear to be companies that offer multi-day Normandy tours out of Paris. Maybe that would let you set yourselves up in Paris for your stay, then depart with a Normandy tour that handled the transportation, guided schedule, and lodging? They’d return you to Paris at the end, for your trip home the next day.

Second MaryPat's recommendation above. Colmar, France is just a short train ride from Basel and is a beautiful town to visit. It's on the way to Paris via Strasbourg. Just a suggestion - especially if you end up looking for a night somewhere in the Basel area after your cruise.

When in Bayeux, don't miss seeing the 900 year old Bayeux Tapestry with its story of the Norman conquest of England.

Also, in the Loire Valley, consider staying in Blois, that is where we stayed when we did the Chateux.

Thanks for all the replies. We will not be driving as we had an incident a few years ago and don't want to relive that experience. I had thought of doing the South of France before heading to Paris which is also a good idea. I was recently in both Colmar and Strasburg and the River Cruise will be stopping in Strasburg as we head down the Rhine/Mosel. It looks like we have the options of taking tours out of Paris to see Normandy and Loire Valley and just base in Paris. I like spending at least 3 days in each location because a lot of time is wasted checking in and out of Hotels. I am also on a waiting list to take Rick Steves 7 days in Paris tour which starts after my river cruise which would leave me with 5 days to do Loire Valley and Normandy. Thanks for all the common sense travel tips because these forums are very helpful

Thank You

I'd discourage taking a day-trip from Paris to Normandy, because a lot of the day will be wasted on a bus tooling up the highway. If you value not changing hotels extremely highly and will be satisfied just to see some of the D-Day sites (missing the Bayeux tapestry, the cathedral, the Invasion Museum in Bayeux, etc.), you should at least consider the full-day tour offered by Overlord and specifically designed for people who take an early morning train up from Paris, are picked up at the Bayeux train station, and then are dropped off at the station in the late afternoon in time to catch the train back to Paris. This should allow more time for seeing the D-Day sites than would a bus tour originating in Paris. Overlord uses vans for its tours, so you'd be in a small group.

Overlord Tour 2FS

Elsewhere on the company's website (https://www.overlordtour.com/which-is-the-best-tour-for-you/ and scroll down), you're informed that to make this tour, you'd have to catch the 7:07 AM train to Caen from Gare St-Lazare and change trains there. However, the current schedule on the SNCF website shows only a weekday 6:58 AM departure (but not requiring a change of trains). The first weekend trains are considerably later and would require a significant change in the tour's departure time and itinerary, but by the time peak tourist season rolls around, there may well be an earlier train on Saturday and Sunday.

I always suggest that those on one-day Overlord tours take something for lunch with them. You cannot eat in the van, but providing your own midday meal will eliminate the time needed to purchase something at the lunchtime stop. For my tour, that was in St-Mere-Eglise, where the Airborne Museum is located. Although there's at least one creperie in town, I don't think one could eat there and still have any significant time for the museum. The other obvious food source was a place selling (decent) pre-made sandwiches for carry-out. If you're going to do that, you may as well take something with you and save that the 5 to 15 minutes needed to buy a sandwich in St-Mere-Eglise.

It's perfectly OK to eat on the train.

You have plenty of time, and if you go Basel - Paris (stay) - Bayeux (stay) - Tours (stay) - CDG then you will not have to deal with any train connections in Paris.
Indeed there is a direct train connection from Caen (short train ride or €60-70 cab ride from Bayeux) to Tours. Timetable is messy, and sometimes there is planned engineering work that shuts down the tracks, but if available it is far better and quicker than going through Paris.
And there are direct TGV trains from St Pierre des Corps, right outside Tours (take a cab), straight to CDG Airport.

So don't let perceived logistics difficulties convince you to daytour Normandy from Paris: it's really not that bad.

Your reasons for not renting a car are understandable. In that case, if the worst case scenario is that you have to go back through Paris when changing from Bayeux to Tours, it’s certainly doable and not the end of the world. I never thought of Caen instead of Bayeux, but even the cab ride, as posted, looks reasonable. Bon voyage.