What’s the best way to get from CDG to Giverny? Taxi from the airport to Giverny or taxi into Paris and then train to Giverny? Giverny is our first stop after our flight from the US.
I should think taxi to Giverny would be costly, it's over an hour. Basically, you need to get to Gare Saint-Lazare to get the TER train to Vernon. From Vernon, you'd have to take a taxi to Giverny. To get to Saint Lazare you could do the taxi or take RER B into Paris and then there are a few different ways to get to Saint Lazare. One would be to get off the RER at Chatelet Les Halles and then take the metro to Saint Lazare. It sounds complicated, it really isn't.
Assuming you have made arrangements for your luggage while you visit Giverny. So many posts on this forum of those seeking a luggage solution, because there don't seem to be many unless you have accommodations in the area.
After a transatlantic flight you are likely to be tired and jet lagged. Be kind to yourselves and take a taxi (ONLY from the official taxi queue outside the airport terminal exit doors) to Gare St Lazare. It is a flat fee. Then the next train to Vernon, which is the town and train station nearest to Giverny. Are you spending the night in Vernon or Giverny? You might ask your hotel to give you the phone number of a local taxi service. There is, of course, a shuttle bus to Monets gardens, but I don't believe they would accommodate luggage. And I don't believe there is luggage storage at the station.