You can go into all nook and corners (after paying an entrance fee), its a public building that recounts the beginnings and glory of the British occupation of India. It was pretty much built for that purpose and never a residence of any kind.

The lifesize diorama of chitpur(barabazar) from about 150 years ago in the Calcutta gallery is worth a look, especially if you plan on going to the GPO/Writer Buidling/Barabazar area later in the day.

They are pretty vigorous in enforcing the no photography rule inside the building, so you will not see many pictures posted about the inside. More here:
http://en.wikipedia.org/wiki/Victori...al_%28India%29

The (former) residence and offices of the Governor of India in then Calcutta is todays Raj Bhavan opposite Eden Gardens. That building is closed to the public. http://en.wikipedia.org/wiki/Raj_Bha...West_Bengal%29