How far do you want to dig, OP? Because what (and how much) you find will depend highly on the time periods and locations in question.
There are some very distinct strata in "Russian" history, and a lot of it has been whitewashed and retconned from the top down to suit later rulers. The process is happening right now with the Russia's internal perception of the 20th century; the only reason it's noticeable is because there are other parts of the world which remember that history a bit differently. Putin's Russia is still grasping around for a national idea, pulling at the memories of tzars and communists alike, but it's already excising or altering "undersirable" information. If the process runs its course with no outside contradictions, a lot of information will be lost - the same way that communists "deleted" things that didn't fit in their world a hundred years ago, and the same way orthodox Christians did with the pagan stuff they supplanted.
So what you have with Russia is, first of all, a territory about which (for a very long time) no one cared, which means a lack of external references and travelogues. Second, you have unreliable history, because it was constantly edited by whoever was in charge. Third, you'll also run into arguments of what "Russia" actually is - Kievan Rus? Muscovy? Novgorod? Do the Poles, Ukrainians, Belorussians, Siberians, or the Caucasus states count - as in, are they part of "Russia" (regardless of whether they are running away screaming from or towards it right now) as "Russia" is defined in your historical query? WHERE, WHEN, and WHO COUNTS will all skew your results differently.
We had a similar thread before (pic related). If you can track it down, there might be something useful to you in there.