Transportation between CDG and Versailles

Below are the options to connect from Paris to Versailles from our France guidebook. You can't go directly from CDG to Versailles, you will have to go into the city to connect. You can take the RER from CDG into town, but you will have to transfer for the C line to get to Versailles. Here are the details:

Getting There
By Train: The town of Versailles is 35 minutes southwest of Paris. Take the RER-C train (4/hour, 35 minutes one-way, €7 round-trip) from any of these Paris RER stops: Gare d’Austerlitz, St. Michel, Musée d’Orsay, Invalides, Pont de l’Alma, or Champ de Mars. You can buy your train tickets at any Métro ticket window in Paris--for no extra cost it will include the connection from that Métro stop to the RER. At the RER station, catch any train listed as “Versailles Château Rive Gauche” (abbreviated to “Versailles Chât”). Versailles Château Rive Gauche is the station closest to the Château (there are two others; ride to the last stop).
At the Versailles Château Rive Gauche train station, exit through the turnstiles (you may need to insert your ticket). Ignore any hawkers peddling guided Versailles tours and tickets (like those at Guidatours). To reach the palace, follow the flow: Turn right out of the station, then left at the first boulevard, and walk 10 minutes. When returning to Paris, catch the first train you see: All trains serve all downtown Paris RER stops on the C line. An hourly shuttle bus (mid-April-Oct only; see page CROSS-REF: Paragraph) links the Versailles Château Rive Gauche train station to a stop near the Trianon/Domaine, but doesn’t go to the palace.
By Taxi: The 30-minute ride (without traffic) between Versailles and Paris costs about €60.
By Car: Get on the périphérique freeway that circles Paris, and take the toll-free A-13 autoroute toward Rouen. Exit at Versailles, follow signs to Versailles Château, and park in the big pay lot at the foot of the Château on Place d’Armes (€6/2 hours, €10/4 hours, €15/8 hours). This is likely the best for most visitors. You can also drive onto the Garden grounds. Entrances are at the Porte St. Antoine (at the park’s northern corner) or from Porte de la Reine; pay €6, then drive past wheat fields, lakes, and small forests to find several car parks by the Petit Trianon, the Hamlet, and the Grand Canal. The car park by the Grand Canal is the most central of these and an easy walk to the Château, but it is tricky to locate and sometimes off limits. You are free to move from one car park to another once you’re on the grounds.

You transfer from RER B from CDG to RER C at Saint-Michel Notre Dame.

Quickest and most-hassle free is not the same as most economical.

Quickest (and most hassle-free) will be by taxi.

Most economical will be by public transport (but then you're going IN to Paris on the RERB and then back OUT of Paris on the RERC).

Somewhere between the two would be a shared shuttle. But its savings depends on how many of you there are. If more than a couple, the difference per person between paying a taxi and reserving a shuttle becomes less and less.

quickest, most hassle-free and economical mode of travel.

You can have 2 out of 3, but not all 3. See above for the options and make the decision based on what you need at the time.