In December, we took the Roissy bus from CDG Terminal 2 to the Opera, where you can catch the Metro. The bus leaves from right outside one of the terminal exits. The cost was about 8 euros per person and you buy your ticket on the bus, so there is no waiting. The trip takes a bit longer than the RER, but we thought the Opera would be a safer metro station to negotiate with bags at night. The bus was only about half full so there was lots of seating.

Ann Widdowson Victoria, BC