My wife and I want to travel as cheaply as possible from GDG to Versailles. I'm assuming we will need to take the train but it doesn't appear there is a train directly from CDG to Versailles. PLEASE HELP us.
You have to take RER B train from the airport into the city of Paris, then switch to RER C train to Versailles.
Use this to plan your journey.
Cheapest and best may be two different things
But cheapest is definitely as described above.
Here are step by step instructions: https://www.paristoversailles.com/paris-to-versailles-by-train-rer/cdg-versailles/