I would be very grateful for any advice that you could provide me with. I am traveling to Paris next year with my family (2 adults and 4 children aged 17, 14, 10 and 8). We do not drive and will be solely reliant on public transport. What is the easiest and quickest way to get from Charles de Gaulle airport to our airbnb rental in Gretz-Armainvilliers? Any help is extremely welcome. Thank you in advance.
The train trip is quite straight forward for CDG to Gretz-Armainvilliers.
Take the RER B from CDG to Gare du Nord, transfer to RER E direction Tournan until Gretz-Armainvilliers.
Visit a ticket office/window at either CDG train station to buy RER tickets for your family. A ticketing agent will customize a ticket for each of you for the trip.