We have 2 55 yr old passengers going from the CDG Airport to the Westin Trianon in Versaille. It doesn't seem reasonable to take the train. What is the best VALUE on getting to Versaille?
Thank you

Train's not bad - RER B from airport to Notre-Dame-Saint Michel stop transfer to RER C which takes you to walking distance of this hotel at its terminus near the Palace of Versailles.

PalQ's route is the simplest and gets you to the Versailles-Rive Gauche station which is closest to the palace. However, a section of the RER C line is currently closed west of St-Michel Notre-Dame. It will re-open in September. To take the RER C to Versailles-Rive Gauche would require a connecting Metro ride to get from the RER B line to the RER C line.

The Westin is closer to the Versailles-Rive Droite station. To get there from CDG, take the RER B to Chatelet Les Halles, Metro line 14 to St-Lazare, and a SNCF train from Gare St-Lazare to Versailles-Rive Droite. Yes, there are transfers involved which means schlepping luggage. But it is the best VALUE. The total cost is E11.15 (same price to go to Versailles-Rive Gauche).

A more costly plan, but one which would eliminate the need to negotiate tunnels and stairs underground, would be to take the Air France bus directly from CDG to Gare Montparnasse (one stop at Gare de Lyon). The bus runs every 30 minutes and costs E12.00. Then take a taxi from Gare Montparnasse to Versailles.

TimS- thanks for the tip about RER C being closed - they have been working on that link for years and trains have always limped along that stretch so hopefully this can be a faster RER line as the name implies.
How about CDG to Gare du Nord then walk thru tunnel to Magenta which i think goes to Saint Lazare or actually Haussman-St-Lazare - the new automated metro - could be easier? But maybe it's a long connection at Nord?

If you were going to take the AF bus to Montparnasse, why not just take the train from Montparnasse to Versailles? It goes to Versailles Chantier which is right about where the Versailles RER C station is. There are runs all day long, I think, and it only takes 15-30 minutes. It would be a lot cheaper to take a taxi from Versailles Chantier with the train fare than from Montparnasse, I'd think. It wouldn't be easier, of course, you'd have to transfer, but I wouldn't think that train fare would cost very much. Although I don't know why Pejota says it isn't reasonable to take the train there, not sure.

PalQ - Yes, if I were doing this, I would take the RER E from Magenta to Haussmann St-Lazare. But I gave the route suggested by the RATP Journey Planner.

Christina - A ticket from Gare Montparnasse to Versailles-Chantiers only costs E2.70. Your route would work well. However, I didn't give it because it would mean more times to transfer luggage, inlcuding liting it on and off of various trains. I'm guessing that if the OP thinks taking the train is not reasonable, schlepping luggage is the key factor.

Does anyone know if RER C is back in operation?

A vote here for the St. Lazare to Versailles RG SNCF train. It is a very nice train, and a no-brainer since you are going from one end of the line to the other. Also, the train stays above ground for nearly the entire journey, give some pretty spectacular views of the Eiffel Tower along the way, particularly at night. We have friends in Versailles and take this train all the time. BTW, it usually leaves from Track No. 1, on the far left of the station while facing all the train tracks.

I just went to journey planner at the RATP site and entered three departure stations: Invalides, St-Michel Notre-Dame, and Gare d'Austerlitz. The planner suggested the RER C all the way to Versailles for each of them. A month ago it suggested a bus from Gare d'Austerlitz to a RER C station further down the line so I assume the full line is open again.