Hi Ben. Great site! We are arriving CDG airport Friday 10pm (13 December), no luggage, and staying at Maison Lafitte, leaving Tuesday evening. We plan to go to Versailles on Sunday. Initially I thought 2 Navigo week cards, but the online purchase site for the Navigo decouvert card times out and is not accessible. Friday is too late to buy the week card. So wondered about 5 day Paris visite card, but expensive. But t+ cards won’t get us out to maison lafitte. What is our best bet? I suspect we get shafted by the system whatever we do! Thanks
This is a rare situation where buying a Paris Visite pass 5-day 5 zone is actually your best option.
Below I'll calculate the total single-use ticket costs for the bare minimum Paris transportation that you'll need:
14.05 € for CDG to Maisons-Laffitte (Friday)
14.05 € return (Tuesday)
Total CDG - Paris ticket cost: 28.10 €
Maisons-Laffitte to Paris is 4.45 each way x2 (for return trip) = 8.90 €
x3 Days (Saturday, Sunday, Monday) is 8.90 x 3 = 26.70 €
Total Paris city visit ticket costs: 26.70 €
Maisons-Laffitte to Versailles = 7.40 €
x2 for return trip = 14.80 €
Total Versailles visit ticket costs: 14.80 €
Total minimum ticket costs: 28.10 + 26.70 + 14.80 = 69.60 €
A single Paris Visite ticket 5-day 5 zone costs 65.80€
And the Paris Visite will cover your entire 5-day trip, everywhere you need to go, without having to organize a stack of single-use tickets (keeping used & unused tickets separate), without worry about mistakes on taking trains, the ability to hop on/off any Metro/Bus/Tram/RER/Transilien train during your trip.
On a side note, the last RER B train from CDG Airport Terminal 2 leaves at 10:59 p.m due to rail works on Friday 13th 2019. Normally the last RER B train from CDG T2 is at 11:50 p.m.
Since you don't have checked luggage, you might still be able to get past passport checks and to either one of the train stations in time to catch the last airport train.
Check out either the CDG T1/T3 to Paris train or CDG T2 to Paris train articles to get a good sense of what you need to do to get to the train stations, buy tickets and board the train. And don't hesitate to ask another question if there are details I haven't covered.