Day Trip to Champagne & Brie from Paris?

My friend & I will be travelling to Paris for a week in late April. I've been told that it's possible to take a day trip to tour Champagne & Brie. We will not have a car, and plan on doing things on the cheap (trust me, we're professionals at getting the max for the min when we travel) by taking public transportation.
Does anyone have any websites I can consult, or tips & points for getting there? Our apartment is in the Marais, if that helps at all.
Thank you, fingers crossed you can help me out!

If you don't have a car, then I would suggest taking a train to Reims. Reims has one of the most beautiful Gothic cathedrals and it is in the middle of the Champagne region so you would be able to go wine-tasting there. The 8:57 am train from Gare de l'Est in Paris takes you to Reims in 45 minutes for 15 euros if you book early.
http://www.voyages-sncf.com/

You can also get info on their tourist office website to go on a wine road tour from Reims to visit wine cellars and champagne estates. I will update this message later with more info, I don't have time right now.


EDIT: OK I'm back. Here is the Reims tourist office website:
http://www.reims-tourism.com/
Avoid going on a Monday, outside Paris a lot of stores close on Mondays (and Sunday).
Other day-trip ideas with public transportation:

1) In the Brie region you can go to the medieval town of Provins : http://www.provins.net/anglais/default.h...
It is accessible by train: http://www.transilien.com/web/site/accue...

3) Go to the Loire Valley, Amboise for instance has a nice castle and Leonardo Da Vinci's last house, le Clos Luc茅:
http://www.chateau-amboise.com/anglais/i...
http://www.amboise-valdeloire.com/index....
http://www.vinci-closluce.com/index.asp?...
It is difficult to go to the other Loire valley castles without a car but you can check with the tourist office if they have any local buses or anything like that.
There are several direct trains from Paris every day that take you there in about 2 hours.

There are dozens of other day-trips possible from Paris by train on the cheap:

- the seaside resort of Deauville, Normandy is 2 hours away
- Chartres (1 hour)
- Mont-St-Michel (3hrs20 + 15 minutes on the bus but really worth it!)
- Beaune in Burgundy, etc.

The sun doesn't set until 9 pm in Paris late April and with twilight it's bright until 9:30 pm, even later if you go west, so you have time to enjoy a full day outside Paris. Anywhere you decide to go it's not always easy to go outside main towns by public transportation (ask tourist offices for local buses) but you can also hitch. It is generally safe and efficient especially if you make a sign with your direction (use common sense of course, nothing is ever 100% safe...).

From the Marais you are a 10-minute m茅tro ride to most train stations in Paris, 15-20 minutes to Gare Montparnasse (trains to Brittany).

When you book a train ticket with the SNCF, the best deals are if you book online 60 to 90 days ahead. The problem is the cheapest tickets are not refundable and cannot be changed, but other good deals are exchangeable and refundable. If you book once you are there it will be a little pricier (except with the transilien going to Provins, you can buy it the day you travel).

Millie already said everything. Except this : if you intend to visit the cathedral and taste the wine/champain, start by the cathedral. (anf get sure you do not miss the train)
have a nice trip.
Last but not least, if you go and visit the cathedral, cast an eye on that "laughing angle", a very specific statue. beacause usually angels do not smile maybe...