I get excited just reading this thread! Of course, I would love to go to all the places mentioned but St. Petersburg, Moscow, The Crimea and Ekaterinburg would be my top choices (I've always wanted to visit Darmstadt too, but that's another thread!).
The level of accomodation means less to me than the chance to see these wonderful places with Bob, Antonio and the other amazing experts on this board. I visited Russia as a student in 1988 on a bare bones budget non-Romanov centered trip and loved every minute of it. The train ride from St. Petersburg (Leningrad then) to Moscow was especially wonderful--staying up late, playing cards and drinking endless cups of sweet tea gave me some of my best travel memories.
I'll stay tuned to this thread and send in my deposit as soon as the trip is set up!
Best to all,
Sarah