Advise on getting between Bayeux and Montreux

I would look into dropping the car on the FRENCH side of Geneve airport. That qualifies as a rental all within France and airport locations should be open on Sundays. From the aiport train station, direct trains around the lake to Montreux run every half hour (plus a few more with a connection). If this choice is not specified when you reserve online, then clarify it with a telephone agent.

Thank you for the info Laura, I think that is what I want to do. I purchased my air fare in and out of Paris and now trying to put together all the details.

Make sure that if you contemplate driving around Switzerland on the way you get a Swiss Vignette for any Swiss green roadsign driving - ie on what the Swiss require the toll Vignette for. It may not look like a multi lane freeway but if it has a Swiss (I mention this because the colours are reversed in France) green road sign or an icon of a car on it you need that Vignette. It will set you back CHF40.

It is not clear from your profile what country you are arriving in Europe from but for most countries (except EU and EEA countries) if you drive in France you are legally required to have a notarized translation of your license into French or (much easier and cheaper) an IDP which serves the same purpose.

Expect over €65 in French tolls and nearly €100 in fuel costs for a small car for that journey.

Thank you Nigel,
I am coming from Houston, Texas into Paris. I am hoping to return the rent car at the airport and then rely on the train to get thru Switzerland.

Also, although the fast TGV Lyria train from Paris to Switzerland is often a logical choice, it's relatively expensive and requires a somewhat inconvenient change of stations in Paris (when coming from Bayeux).

yes, before I had the idea of driving the rent car toward Montreux, I struggled with the thought of trying to transfer from station to station with my main suitcase plus a smaller carry-on bag and a camera bag.