Metro is definitely the simplest and fastest way to reach the Kremlin from the D'Hotel. From VDNKh Metro Station (around 300m from the hotel), travel south on the orange line five stops to Turgenevskaya. Change there to the red line and head east three stops to Biblioteka im. Lenina. Follow signs for the Kremlin from the platform to emerge right next to the main visitor entrance in the Kutafya Tower.
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