We visited Claude Monet's House in Giverny France in August.
We were staying at the Renaissance La Defense and took the train from La Defense to Gare St Lazare. From there you get the train to Rouen getting off at Vernon. Then you take a short bus ride to Giverny. The bus timetable lines up with the trains, we did not wait long for the bus to come.
It is best to go early as the house and gardens do get busy with bus loads of tourists.
We found it easy to go by ourselves, there is no need to pay the expensive fees for a bus tour there.
If you have any interest in Monet, it is well worth a visit.The house has some very good Japanese prints and the gardens are beautiful.