Here is what you can do when you get to CDG to go to Orly. We are doing the same, probably taking the Air France Cars but you can take the Orly Val connection too.

RER Line B + Orlyval (connection in Antony)

Hours : 6 am to 10:30 pm*
Frequency : 4 to 8 minutes
Fare : 16.35 EUR* /



Air France Coach

Line 3 : Orly / Roissy CDG

Departure from Roissy CDG :
Roissy CDG 2 A and 2C : Exit 2 from 2 C
Roissy CDG 2 B and 2D : Exit 1 from 2 B
Roissy CDG 2 E and 2F : Exit 3 on the gallery
Roissy CDG 1 : Exit 34 - Arrivals Level



Hope this helps.