Rental Car Drop-Off---Gare Saint Germain en Laye?

I am looking for an EASY rental car drop-off for our trip back from Normandy to Paris in the 7th Arrondisement. We will be stopping at Giverny along the way. I would like to avoid "white knuckle" Paris dense traffic and desire straightforward location finding! Does anyone know if it would be economically reasonable to drop-off the rental car at the Europcar station next Gare Saint Germain en Laye in the Paris outskirts and then take a taxi to the 7th Arrondisement? This location appears to be still sufficiently "rural" with Google Earth. Would someone know a better Europcar drop-off location? I would prefer avoiding an extra RER train run inbound to Paris Gare Saint Lazare and then to a taxi with our luggage, etc. Thanks in advance for suggestions.