Hi, Nathan! I'd like to advise you St.-Petersburg for your Russian trip. This is very beautiful city in Russia. Sankt-Petersburg also called "Nothern Venezia". There are a lot of channels, bridges and old-fashioned houses. This city was the capital of Russian from XVIII to XX centuries. One of Russian famous emperor, Peter the Great, was the main creator of this city. I had visited this gorgeous city no less than triple and I could say that always was great.
Also I think it could be interesting for you if you come to Volgograd may be only for one weekend. (I can’t be quiet because it’s the city of my staying ))). My city is the city hero (Do you something about Stalingrad? Volgograd = Stalingrad). The one of the most gory battle in WW2 is the Stalingrad battle (Did you see “Enemy at the Gates”, 2001? This is about Stalingrad battle.). So, Volgograd full of memorials of events of WW2. If you are interested in history that could be very interesting tour for you.