How do I get from the hotel to the Tretyakov Gallery?

From Mendeleevskaya Station, located underneath the Novotel Moscow Center, travel two stops south to Chekhovskaya, and change there to Tverskaya and the dark-green line. Continue two stops south again to Novokuznetskaya Station, and exit via the interchange station Tretyakovskaya. This will bring you out about five minutes' walk from the gallery, which is clearly signposted from the metro.