With all your help, I found a nice hotel in Le Marais.

Now, can anyone let me know as to how can I go from CDG airport to Le Marais area (Saint Paul station) - a reasonable alternative would be great and how long is the commute?

We just did that in April. We used the RER from CDG and took the KROL express train, first stop Gare du Nord. We got off at Chatelet and followed signs for line 1 direction Chateau de Vincennes. Go 2 stops to St. Paul. It takes about 1 hour total from getting out of terminal on to train out at St. Paul. That of course is average. It could be more or less. Approximately 8 euros.

Agree w/ opaldog's detailed advice. If you take a non-express RER it only adds 10 minutes or so.

One other suggestion. Try to have some Euro coins (hit an ATM and buy gum or just ask a vendor for come change) ready for getting your train ticket.

The manned ticket window lines for the trains at CDG airport can be awful (20-30 minutes?) and the ticket machines won't accept US credit cards since they don't have the computer chip (although US credit cards will work elsewhere throughout Paris).

Thank you so much this was very helpful...

Take the first RER train available. While the ride itself will be shorter on the express, you'll lose time if you pass up a regular train and wait for an express.

Just wanted to let you know that it can be very difficult to find an elevator in the metro stations, so you'll be bringing your luggage up escalators. When we did it, one of the long escalators was out of service, so we had to carry our bags up the long flight of stairs (we had three kids and their bags with us, too.) So if you ride the train rather than taking a cab or shuttle, be sure you are physically capable of carrying your luggage, just in case.

bumping