So with the capitol building, I started by going on site to take some reference pictures. After getting the pictures into Maya as image plans. I did a very quick mass out of the model to get a general idea of how to brake up the model-- and how many tris. I could use for the key parts of the building; namely the dome and columns.
The model had a 5K tri. limit-- and in the end, I ended up de-res then upper columns and removing the backs of them. The top columns do have space in between them and the wall behind them. However, as you rotate around the building, the wall behind them is close enough that you never see their back side. The stairs are a simple ramp. Lastly, all the railings are single plans that will be broken up with an alpha channel.