Bath to Normandy

The first bit is easy- hourly train Bath to Portsmouth (either station), travel time 2 hours 15 minutes, walk the mile and a bit (or taxi) to the Continental Ferry Terminal.
Unlike Eurostar no immigration issues.

All that is a walk in the park.

Cherbourg port has moved further out of town. Personally I would do the Ouistreham (Caen) or Le Havre crossing. Caen overnight has a bus to the train station, Le Havre you can walk to the station- done that a fair few times.

Or, here's the curve ball. Train Bath to Plymouth, then ferry to Roscoff. Plymouth ferry port is a bit grim, but Roscoff port and town is my favourite French ferry port hands down. Take a taxi from Plymouth station to port- I've walked it, don't follow my lead in that.

Others can advise you of the rest, now you have arrived in France.

Depending on your final itinerary...if you are in Brittany, drop your car rental off at the Rennes train station and take the train into Paris.
Though that was from central Paris, so you'd need to then go Paris to CDG. (We did Paris to Rennes, picked up the car rental, then stayed one night in Pontorson to visit Mont St Michel. We only had one night, but probably could have found lots of other interesting places to stay/visit, and many on this forum who will make good suggestions. We went with convenience with Pontorson, which was a cute little town. Then we explored Normandy, staying in Bayeux and Rouen.

Driving in the Normandy/Brittany regions is so easy, and the roads are well maintained.

lhdunlap,
The transportation suggestions above are good, but I hope you allow sufficient time in Normandy and Brittany. I would allow five days in Brittany alone, plus five in Normandy. There is much to see and enjoy in both locations.

Have a great visit to western France!

For info, we're taking the ferry from Portsmouth to Ouistreham (port of Caen) in September and then renting a car from the Caen train station for a couple of weeks. The Brittany Ferries website is really pretty good - can research there to see if they include Le Havre or Cherbourg, if that's your preference.

Before I offer thanks on replies, I request additional information on transportation from Bath to Portsmouth. It doesn't appear possible to catch early morning train from Bath and arrive Portsmouth in time for same morning ferry departure. There is a 1500 ferry but we do not desire to arrive Brittany at 2200. For mid-September dates, National Rail website shows "rail replacement service, all or part of this journey will be by bus".

https://www.nationalrail.co.uk/
If this is the case, I may need to leave Bath on Saturday 14 September and spend 1-night in Portsmouth, before departing 0800 Sunday on Brittany Ferry to Caen.

Lastly, thank you to all prior responses! Judy convinced us to spend 5-nights in Normandy and 5-nights in Brittany. Robert educated me on ferry to Caen and rental car options. I appreciated isn31c and KD opening my eyes with curve ball options.

Just to play devils advocate- you could do the whole thing by train. Bath to London to Paris to Caen, and arrive in time for dinner. But you would have to change stations in London and Paris.

Even without bus replacements for engineering work you couldn't get from Bath to Portsmouth by train on a Sunday in time for a mid morning ferry departure.

Bearing in mind that the Ferry Port is a walk or short taxi ride round from either railway station, and that Portsmouth is a bus boarding port. That is there are not gangways from the terminal to the ship. You board a bus from the terminal to the ship's gangway (a sometimes comically short ride)- all of which adds a little bit more time to the equation. Some of the berths are close enough to walk, but you aren't allowed to. Health and Safety. I can remember when you were allowed to walk to the ship.

So yes on that route, if you don't want the afternoon sailing you would have to stay the previous night in Portsmouth (and take the chance to visit the Historic Dockyard, or maybe the Isle of Wight!!, or other options in the City). That to me would be a bonus, to have extra time in Portsmouth.

Robert, I hope you will bookmark this discussion, so you can come back and give a short report after the trip. Thank you in advance. Lhdunlap's report would also help others, but the thread may automatically lock by the time of a distant trip.

Sure. Will do.
FWIW, we opted for the ferry so we could visit the D-Day museum in Portsmouth on the way over to Normandy to visit the sites there.
We know from past experience that we'll be dealing with jet lag for the first few days of the trip so the idea of booking a stateroom on the ferry was particularly attractive for us. The plan (hope) is to be able to take a power nap during the crossing in order to stoke our immune systems and generally get ready for an active couple of weeks in Northern France.
Will let you know how it goes ...

The first two minutes of this new video from The Man in Seat 61 shows you how easy getting to and navigating Portsmouth Continental Ferry Terminal is- https://www.youtube.com/watch?v=s4PNVkZ59yQ

(the rest of it shows you the crossing to Santander for Madrid- the really stylish way to Spain) .

In this modern building (if you look carefully) there is a memorial to a Crimean War Victoria Cross Winner whose grave is beneath the port Car Park (the former Portsea Island General Cemetery).

lhdunlap,
It just occurred to me that your 5 nights in Normandy don't all have to be centered on the DDay landings, etc. Normandy encompasses a large territory, and I highly recommend Rouen. It is a beautiful medieval city with, of course, the cathedral which Monet painted so often, the Joan of Arc connection, and a charming old quarter with half-timbered buildings. Between Rouen and Bayeux is the Route des Abbayes, with several abbeys you could visit. The most compelling one is Jumiege. Magnificent ruins! When you decide on your route, if it contains parts east of Bayeux, do yourself a favor and stop at Rouen, and take the smaller road which follows the Seine River and see the Abbey of Jumiege also.
I envy you your trip. Amusez-vous bien and bon voyage!

A bit late to the game perhaps, but it would be easier IMO to do England -> Brittany -> Normandy with the help of the London Gatwick -> Rennes flight or the Bristol -> Nantes flights.

Many thanks to all RS travelers for thoughtful posts. With your input, my wife & I have modified our itinerary. Here is new itinerary:
- 0625 Tuesday 20 August, Arrive Heathrow. Train to Bath. (This is first modification. Begin trip in Bath and then proceed to London).
- Sunday 25 August, train from Bath to London. (Special heads-up. Airbnb host alerted us Notting Hill Carnival runs Saturday 24 August – Monday 26 August, link: https://nhcarnival.org/
Expect major London traffic detours. Host says this is huge event where people travel from other countries to experience.
- Sunday 15 September, Eurostar Train from London to Paris. (Second modification. Thank you CJean and others who suggested train option to France. By switching order of Bath and London, train became efficient transportation. We just couldn’t sync train from Bath with ferries). Train from Paris to Bayeux. Pick-up rental car.
- Thursday 19 September, drive from Bayeux to Dinard. (Special thanks to Robert who suggested Dinard as home base for Brittany! RS suggests Dinan or St. Malo as home base. There is an easy foot ferry which regularly crosses bay between Dinard and St. Malo. We can easily visit St. Malo without having to deal with parking, lodging or crowds.). On Airbnb we reserved a lovely Dinard waterfront apartment with bay views from all 3 rooms.

- Tuesday 24 September, drive from Dinard to TBD, return rental car. (RS travelers, please suggest destination for rental car return). Train to Paris CDG. Hotel room at CDG.
- 1050 Wednesday 25 September, flights from CDG to SAN.
Again, thank you all for your valuable input!

You could return the car in Rennes, at the station. Rennes traffic is annoying between 7-9 and 4.30-7, and the car rental location is up a tight 10-story car park, but it works.
Or in St Malo, perhaps.

Don't overlook 90 minute check-in requirement for Eurostar, and likely need to change between stations in Paris.