What's the best way to get from Gare Du Nord to Quai Maurice Berteaux 78230 Le Pecq if we want the fewest transfers for the cheapest price?
The cheapest way will be to use the RER taking about an hour, but this means you will have to transfer lines. The ticket costs under €5 and you use it for both trains. You can buy these at the machines in any station.
From Gare Du Nord you take either the B or D line to Châtelet - Les Halles. (The train will read as GARE DE CORBEIL, and you get off on the first stop)
From Châtelet - Les Halles you then change trains and take the A line to Le Vésinet - Le Pecq. (The train will read GARE DE ST GERMAIN and you'll ride it 10 stops)
From there you then have a 16 minute walk to board the ship. Alternatively it will take around 45 minutes in a taxi, but will cost considerably more.
This is a map of line B, you want to take the train eastbound from Gare Du Nord one stop to Châtelet-les Halles.
Then you want to change to the A line and take the train westbound to Saint Germain-en-Laye.
From there according to Google Maps it is a 19-minute walk:
From the station walk to GARE DE ST-GERMAIN-EN-LAYE and take the line 01 bus towards GARE DE RUEIL-MALMAISON and get off at PONT DU PECQ, from there it is only a 1 minute walk, the route is shown below:
Similar journeys can be planned on this site.