How to get from Reims to Epernay w/o a car-need advice!
 

Wanted to know if it makes sense to take a train from Paris to Reims-( want to see cathedral) and then, we have a private tasting in Epernay at Pol Roger at 2 pm- Am I trying to see too much in a day? How many Euros for a cab from Reims to Epernay and how long does the drive take? Lastly a train from Epernay back to Paris.
Thank you in advance for advice...

Frequent trains links Reims and Eperny as well. And the Epernay station should be a short enough stroll from anything in this not to big town.

The Reims Cathedral is also walkable enough from Reims train station.

Trains are OK to get from Paris , but if you have a limited time to travel from Reims to Epernay the trains might not work in with your schedule , I decided to have lunch in Reims because there are much better restaurants in Reims , but I have to be at Epernay, Moet @ Chandon within 40 minutes of lunch , so I will get a taxi the cost approximately 38 euros and should take about 35 minutes by taxi the distance is approximately 24 kms.
I feel this is worth the price difference of the trains "15 Euros", for an extra few euros , I get to do everything on my wish list . Good luck with your trip, and Bon Voyage !