CDG to defence district

This is the way to figure it out:
http://www.ratp.fr/en/ratp/c_21879/visiting-paris/

Take RER line B to Chatelet-Les Halles and then change to RER Line A to La Defence. Note that this will be travelling from outside central Paris to outside central Paris, so you'll need to buy specific tickets between those two stations.

Thanks , looks fairly straight forward

It may help you in further research if you have the correct spelling of your destination, it is La Défense.

If you take the RER to Chatelet/Les Halles you can get the #1 metro to LaDefense for 10 Euro CDG/Paris ticket. If you take the RER from Chatelet/Les Halles you will need a more expensive ticket CDG/LaDefense. La Defense is not in Paris; if you have a choice I'd recommend getting a more central hotel.

We are staying at the Hilton which from what I can see is right at the subway and train stop. We plan on taking the subway back into the center of paris to enjoy the sights .

It isn't just the distance, it is being in a big office park that closes down at night and lacks anything of Parisian charm. If you are in Paris, it is easy to wander out for a drink in the evening or stroll along the Seine. If you are back at the hotel, you aren't likely to do that sort of thing when it means an hour round trip and the hassle.

Janet knows of what she speaks.
Are you sure you want to stay there? It's not really Paris.

In my experience, La Defense rates with Dubai and Las Vegas for feeling isolated and artificial (although the other two have lots more restaurants.)

Thanks for all the info, will take it all into consideration

Dave,
I will also be in Paris the end of September and early October. I had looked at the Hilton you mentioned and almost booked it. In stead I am in a studio apartment in the Porte Saint Martin area right at the edge of the Marais. Top floor sleeps two and an elevator. Not to complain because it is less than 75 dollars a night. but central. Just down the Blvd from the Gallaries Layayette and Opera. La' Defense is really isolated from the essence of Paris.

There's a Hilton in Paris across from the St. Lazare train station, behind the Galeries Lafayette department store. Could you use your points there?

I think we checked and didn't quite have enough points . We stayed at a holiday inn near the opera district a few years ago , and had no problem getting around on the subway and loved being in that area . I know this is outside the main areas of paris but being only a 10-15 minute subway ride into the center of Paris and the subway takes us right into the hotel .i know it's not the old paris with the modern hotel and shops but hopefully it will be ok