We just returned from this tour two weeks ago. We had a great time as I’m sure you will also. We arrived in Reims the day before the tour started. We visited Taittinger cellars on our own. They have several English tours throughout the day. You can go to their website and check times. We purchased tickets online, but there were people that just showed up. It was a good tour and tasting. Our Rick Steve’s tour visited Pommery cellars. You could check with the office to see if that will be the case with your tour, so you don’t repeat it on your own. We took the bus to get to Taittinger, and it was very easy to get to.
We also visited Museum Of Surrender of Reims, which is where the Germans signed their surrender documents at the end of WWII. Small museum, reasonably priced, easy to get to and interesting if you’re interested in WWII history at all.
Make sure you see the cathedral at night. It’s beautiful. They also do a light show, which we didn’t see as we were there the end of May and they didn’t start that until June. Not sure how long in the season they run the show, but even just lit up, the cathedral is beautiful. Enjoy!