Hi Patrick,
Just a few things to note:
- ticket jeunes are valid only for Sat./Sun./holidays, (not available on Fridays)
- ticket Mobilis are not valid for the Orlyval, nor Orlybus, but is valid for the Orly RATP shuttle bus between Orly terminals and RER C train station Pont de Rungis.
But, the ticket Jeunes is not valid for the Orly RATP shuttle bus between Pont de Rungis.
RATP city Buses 183 et 285 are both valid options for either Ticket Mobilis or Ticket Jeunes.
Horribly confusing, I know,
see this for more information (in French).
Having said all that, it might be simpler to purchase
Carte Paris Visite 2 days, 6 zones for the entire family which will cover you for all your travel. In addition,
Orly Airport is covered, even the Orlyval train to Antony station on the RER B line.
2 day 6 Zone Paris Visite is 27,50€ for adults. Child fare is 13,75€. (
Full price list).
Don't hesitate to ask if you have further questions,
Ben