Twisting up the theme, excluding the obvious moral points of focus, would a regular 19th century Russian have access to pawnbrokers? Does the sentence the protagonist gets an accurate depiction of the punishments one would receive after committing murder in the 1800s? Is his cramped conditions an accurate depiction of the citizenry of St Petersburg?
Short answer: Yes!
Dostoyevsky frequently used contemporary Russian society as a setting for his short stories and novels. You can see similar depictions of Russian society in the works of other authors, such as Gogol's depiction of the life of a civil servant in "The Overcoat", or Lermontov's description of Russian provincial life in "Hero of our Time". These men, by and large, had either lived through or had secondhand experience with the lifestyles they described in fiction, and are quite reliable in faithfully interpreting daily existence in their stories.
The punishment itself is not unusual either. Given the vast expanse of the Russian Empire, isolation and exile to the far reaches of the empire were not unusual punishments. We in the West tend to think of the gulag as a Stalinist invention, but in reality, tsarist-era internal exiles and segregation from society were quite common. The expanse of Siberia made it a convenient place to send criminals, especially given the bloated bureaucratic apparatus of the 19th century Russian state.
As for the life of our superman Raskolnikov, Dosteyevsky's depiction is quite faithful. The average civil servant in St. Petersburg frequently lived in cramped quarters, often sharing a room with one or many others, and would certainly have a personal relationship with the landlord. Of course, not all these relationships ended in axe murder, but sometimes that's just the price of being a greedy old pawnbroker.