Loire Valley using Public Transportation

The train between Blois and Amboise (St-Pierre) is direct and takes 30m. I would use both Blois and Amboise as home bases and visit Cheverny and Chambord from Blois, and Château du Clos Luce and Château de Chenonceau from Amboise.
From Blois you can take a direct 45m bus to Château de Chambord and back. In the afternoon, take a direct bus (30m) between Blois and Château du Cheverny.
From Amboise you can take a direct bus to Château du Chenonceau in the morning and back and in the afternoon you can walk to Château du Clos Lucé from Amboise (15m).

Thanks MaryPat

Sounds pretty straight forward

You might want to check options for minivan tours, too. I took one when I was there in 2019. They usually stop at 2-4 chateaus, depending on the tour and whether it’s a half-day or full day. I was based in Tours.

By the way, I don’t know the rest of your destinations, but one of my favorite days was going through the fortress at Angers. In fact, I took one day away from the chateaus to stay in Angers, instead, and was happy I did it. Thought I should mention it since you’re in the vicinity.

From Blois you can take a direct 45m train to Château de Chambord and back.

Interesting, I was unaware of any train between Blois and Château Chambord. Actually I was unaware of any train nearer to Château Chamboard than the train station at Blois itself.

Did you personally use this train to go to Chambord?

I wouldn't bother making a distiction between castles and chateaux - you never know where you might end up. They are all chateaux

I would base in one town for your whole visit, either Blois or Amboise, doesn't make much difference. Changing bases will cost you half a day, despite the fact you are only moving 20 miles down the road.

From Blois you can catch a shuttle bus (in season) to Chambord and Cheverny.

Amboise chateau and Clos Lucé are only a 10 minute walk apart

The only outlier is Chenonceau. In Amboise you can rent a bike to ride to Chenonceau, it's about 10 miles each way. Bikes are available from the Tourist Office.

Chateau de Chenonceau has a handy train station just opposite the car park. 26 minutes on a TER from Tours, if you are around there. This isn't Germany or Switzerland so the train isn't every hour, or even to the same final destination. But these are real trains and they do serve the chateau. I've seen them.

There is information on the how to get here page of the chateau. https://www.chenonceau.com/en/practical-information/how-to-get-here/

If you like cycling, I have done the route from Blois to Chambord and highly recommend the bike as a way to get to Chambord. There are bike rental places in Blois near to the train station or to the Chateau de Blois.

From Blois you can take a direct 45m train to Château de Chambord

Careful. There is no train service to Chambord that I am aware of, or that shows up on Google.

Thank everyone for your feedback and insights!

On another forum several people said to just use Tours as a base. 🤔🤔🤔

Without a car, I think Tours is a great location with plenty of restaurants, cafés, shopping, and a few museums. However, I would only stay on the north side of Tours near Old Tours and Tours Centre (the train station) as other parts of the city are not of particular interest to tourists.

No Tocard, I did not take the train from Blois to Château de Chambord but according to: https://reiseauskunft.bahn.de/bin/query.exe/en?ld=4312&protocol=https:&seqnr=30&ident=nk.02928012.1623110195&rt=1&OK#hfsseq1|ay.02951412.162311557
Correction, this is a bus not a train.

My daughter and I spent 3 nights in Amboise (June 2016), and visited all the castles you mentioned without a car.
One morning we took a public bus to Chenonceau (our favorite!)
The following day we took the train to Blois and then a shuttle bus to Chambord and Cheverny.
I’d suggest you check RS France guidebook for more details.

Enjoy your trip to beautiful France!

Edited to add:
The only drawback of traveling via bus or shuttle is that your chateau visit is somewhat limited because you’ll need to get back to the bus stop within two hours.

It is important when answering a question using the internet to carefully understand the answer. The detail for the Blois to Chambord train is that it isn't to Chambord - in other words not to a named train station - but it is to Château de Chambord, the Bahn way of identifying a bus stop. It is in fact a bus, specifically a bus which just goes between the two places, roughly once an hour but because it takes 35 minutes with a layover before the return the time isn't the same every hour, it moves forward.

It is most helpful to give advice based on personal experience, but if not I try to mention where I get information that I don't personally know.

I want to encourage everybody to help with questions and opinion is very valuable, but when it comes to providing facts that will be relied upon it is so important that they be accurate.

Information on the Bahn website and app is exceptionally accurate and comprehensive but it takes drilling down and sense checking to understand exactly what is being presented - especially for regional and local transportation for example...

For what it's worth, I used Tours as a base about five years ago and loved it. I used public transportation and a tour service to see Amboise, Clos Luce, Chambord and Chenonceau and then did some great wine tasting in Vouvray. The Tours Office of Tourism was very, very helpful in helping me get around. The city is very beautiful with a small museum of fine arts, some beautiful churches, and great restaurants, especially Dagobert.

Good luck

Here is the link for seasonal bus service from Blois to Châteaux Chambord/Cheverny:

Chambord has no train service closer than the TER trains servicing Blois.

Alternatively, Blois and Amboise are both on the regional TER Train line between Tours and Orléans/Paris.

Only thing I know for sure is that there is a train stop at the entrance to Chenonceau.

The train to Chenonceaux never quite reached Château Chenonceau. Sometime in the last decade or so, the tracks were extended to the château property entrance. I don´t think anyone rode the train to Chenonceaux who were not going to visit the château anyway.

Forgot to check if it was a bus or train, thank you Nigel and I corrected both posts.

Sembach,
As previously mentioned, my daughter and I took a public bus from Amboise (across the street from Theater) to Chateau de Chenonceau, the bus stops in front of the castle gate.

I did a bit of research and found the bus that my daughter and I took from Amboise to Chenonceau castle.
If you plan to stay in Amboise, I'd urge you to go to the TI office as they were very helpful.
They will provide you with a map and will mark where the bus stop is located.

Here is the link to the bus https://www.remi-centrevaldeloire.fr/itineraire/

You can see the bus schedule by choosing your desired departure and arrival as follows:

• Départ: type Amboise and choose, "Théâtre (Amboise - 37)"
• Arrivee: type Chenonceau, and choose, ''Château de Chenonceau (Indre-et-Loire - )''
• choose desired date
• choose a time in the morning, say 8am

We took the bus "C" in Amboise at 9:53am and arrived to the castle stop at around 10:21. We then took the bus back to Amboise at around 12:20pm

Here is the bus schedule

The top schedule is the one you need for the return; Chateau de Chenonceau to Amboise (bus originates in Montrichard)
The bottom schedule is the one you need to go from Amboise to Chenonceau (bus originates in Tours)

Tocard already provided you with the link to the bus shuttle if you want to visit Chambord and Cheverly.
The location of this bus is a bit tricky as there was no signage when we were there.
When you exit the Blois train station, turn left and go past the parking lot and into another parking lot where you will see the shuttle buses parked.

If you decide to stay in Amboise, make sure you plan to eat a delicious meal at Chez Bruno (reservations required)

Hope this helps!

Edited to add:
I forgot to mention that the public bus (Amboise to Chenonceau) does not run on Sundays.

@priscilla - thank you so much for this helpful detailed information about the bus! My husband, "tween" daughter and I will be staying in Amboise for a few days in August and will not have a car (it's a short 3 day trip from Paris where we will be staying for most of August). We are only interested in visiting Chenonceau so taking the bus will be perfect for us. We plan to spend the rest of our time in the Loire riding bikes, swimming in the hotel pool and relaxing! Thank you again!

Priscilla - thanks so much for the detailed info!