Is it possible to go directly to Versailles from the CDG airport? If not, what would be the fastest route? Thanks.
No, you cannot go directly. Take the RER B to St-Michel Notre-Dame. Transfer to the RER C and take it to Versailles-Rive Gauche. The RER C line divides on the west side of Paris. Be sure to get on a train that is going to Versailles-Rive Gauche (all trains with the nameplate VICK).
For a zoomable map of the Metro and RER system, go here.
You could also take a private shuttle from CDG for a mere 115E...
The RER will be (ever so slightly) cheaper, though.
I would avoid going into Paris. Do a search for bus routes between these two points.
A bus will be cheaper and take less time
CDG to Versailles by RER takes a maximum of 1hr40min.
Going by bus requires four changes and takes over three hours.
After flying from Bothel, WA to CDG you will be near death from exhaustion!
Plan your trip to Versailles after you are well rested!