yeah the hotel is really nice and it's in the very center, near all tourist attractions in a walking distance, but you should book room there in advance of course, in the summer - there are a lot of tourists, when do you want to visit the city?
will you go to moscow by train? and did you do this program yourself or you visit the city with a group? I didn't understood your confusion with train works even with a picture ( but may be I will help you with orientation in the city when you are here