Labor Day, May 1, 2020 in Bordeaux

Maybe we don't know any better but in Bordeaux we found interest and enjoyed our time visiting the Cite du Vin (Wine Museum)
https://www.laciteduvin.com/en/plan-your-visit/practical-information

And it appears you can a get a ticket for May 1 2020

https://ticket.laciteduvin.com/en-GB/home

Yes, Bordeaux is not Paris or Lyon. But there's plenty to do in Bordeaux for a day; I really enjoyed the historic part of town. In addition, there's an excellent prepared-food market just beyond the Cite du Vin; offerings looked enticing. I believe there are a couple of art museums as well.

I am not at all interested in wine but still enjoyed a day-trip by train to St-Emilion. St-Emilion is distinctly hilly but very picturesque. The lower part of the town is very touristy, a situation which I am sure would not be improved on a major holiday--which in this case is part of a 3-day weekend. But I'd still be willing to go. There are probably wine-tasting opportunities, but I don't know anything about those.

The train takes about 35 minutes, but service (at least on May 1) is only every two hours for a good part of the day. You can check the schedule on the SNCF website. The website is a bit funky at the moment. I initially got no results for May 1, but after using the large date circles at the top to switch to April 30 (which did show trains) and then back to May 1, I was able to see the schedule. I hope what I'm seeing is an accurate schedule for the holiday. It's a regional train, so you needn't buy tickets in advance; you can make a decision on the day, based on weather and your energy level. There would be no savings from buying early, and the seats are not reserved. It appears a round-trip ticket will cost about 20 euros. There's a little shuttle from the train station to the town. You'd probably want to use it in at least one direction, because the walk does take some time. I think the navette cost me 4 euros. It will take you up to the top of the town; you can wander slowly downhill from there. There's a tourist office up near the top; I don't know what hours it will be keeping on Labor Day.

The steepest cobbled streets in St-Emilion can be treacherous when wet, so either skip this trip if the day is significantly rainy or be very careful. I managed not to fall, and I'm a klutz, but it would be easy to take a tumble. The footing on the streets in the busier, more touristy lower part of town isn't as tricky, but I like to see the out-of-the-way places.

There might be tours from Bordeaux going to St-Emilion. More costly (and you'd almost certainly need to pre-pay to be sure of having places on the tour), but such a tour might also go to a second town.

If St-Emilion for some reason doesn't appeal, I can recommend a couple of towns east of Bordeaux where I enjoyed a visit of a day or longer as I was trying to see the Dordogne by public transportation: Perigueux (on the Isle River, at least 76 minutes from Bordeaux by relatively infrequent train) and Bergerac (on the Dordogne River, 1-1/4 hours from Bordeaux by trains running every 2 hours). My first choice would be Perigueux.

Believe me, Bordeaux is not the only thing you and I disagree on.

In this case, the poster is already scheduled to be in Bordeaux. It's not necessarily going to be easy to not be in Bordeaux on the day when the canceled wine tour was originally scheduled.

Folks who made suggestions —thank you! Folks who don’t like city of Bordeaux—I am sorry—your commentary not helpful.
We are traveling on Viking River Cruise and doing many wineries in area—nice to hear of personal experiences. Just one winery canceled, due to May 1st. Decided to befriend Forseti chef and go to market for the morning and walk and check out coffee shops before our ship leaves area. Although, if we had more time, we would definitely visit the wine museum. Thank you to all who made suggestions.