sny suggestions on how to split up 10 days in Brittenay. all out of 1 location? where ? or do do gites for splitting north and south?

best railroad station to take in from Paris and back out?

Check out my trip report from 2 months ago: The Peabody Papers 2019, Paris and Brittany, Unmapped

Also look at Stu Dudley's posts.

I don't think Brittany very well suited to a single base -- I'd recommend at least two bases, whether north and south or east and west or whatever, depending on your specific interests.

As I understand it, much of central Rennes is currently undergoing renovations that many find disruptive, but otherwise, its a great rail option for ready access from Paris.

If you don't already have it, I'd strongly recommend the Michelin Green Guide.

To see the various sights such as towns like Concarneau and Pont Aven, the calvaries and the menhirs, you will need a car. Either go to Rennes, pick up a car and develop a circular itinerary for Brittany, or take the train to Quimper and zig-zig back east to drop off the car in Rennes or even Paris. The Michelin Green Guide is useful.
https://flic.kr/p/8sTCQghttps://flic.kr/p/8sWMddhttps://flic.kr/p/8sWuBLhttps://flic.kr/s/aHsjrz9U32

Interesting post. I have ancestors who emigrated from Rennes to Quebec c. 1700, so visiting there is on my to-do list to trace back records before 1600.

Ten days isn't much time to spend in Brittany. Best plan is to perhaps take the TGV from Paris Montparnasse to Vannes, spend 5 nights there visiting the area around Vannes. Then drive to Dinan, visiting Josselin Chateau on the way. Then spend 5 nights near Dinan (don't stay in St Malo). Take the TGV back to Paris from St Malo - there is a direct noon train.

See attached

Stu Dudley

having trouble finding the direct train from St Malo to CDG

There is no direct train to CDG. The once-daily direct train goes to Paris Montparnasse station, and departs around noon. You can get off this same train in Le Mans, and transfer to a train to CDG that gets to CDG about 5:15. There is a 1 3/4 hr layover in Le Mans.

Stu Dudley

That's because there isn't one.

Oops, was cross-posting with Stu.

I do see 2 directs from Rennes to CDG no transfers $36

I have been following this thread as we have 21 days in Brittany in April 2020, and I was trying to work it all out from one base. StuDudley I will take your suggestions and use 3 bases. Thanks so much.

there are a couple direct TGVs from Rennes to Lille which have a stop at CDG.

see
https://en.oui.sncf/en/train/timetables/rennes/lille

The season when you travel is also an important criterion to answer. If you prefer only one location, and enjoy staying in cities, then Rennes is the central and easy choice. From there you can easily do many day trips, and the city itself is pleasant.
Otherwise, 2 bases would be a good compromise : one on the south coast (Vannes, Quimper...) and one on the north (especially St Malo, if you want to rely on public transport).