Wanking Poland makes wanking Russia rather difficult, since once Poland gets beyond a certain size it tends to block Russian expansion into the Balkans, and the territories lost in Ukraine, Belarus and the Baltic states aren't easily made up for easily. It strikes me that it's easier to wank Russia at the expense of the Poles or into the Balkans than elsewhere: sure, you can add sheer territory in parts of Asia, but not much in the way of easily assimilated populations. When one wanks Poland, one usually diminishes Russia: [1] if one needs to wank Russia, you need to make up for these losses so Russia overall is _bigger_ than OTL, and OTL Russia was probably pretty close to topping out on growth in any event. Where do you go beyond 1914 OTL?
To the south are either relatively dense and very hostile to conquest Muslim populations in Turkey, Iran and Afghanistan or howling wastelands like Mongolia and the Tarim basin, and Tibet if you keep going, (there's that sheer territory I was talking about) while to the east are a zillion xenophobic Chinese, the Fairly Indomitable Japanese, and the Koreans, which according to democracy101 are impossible to conquer before 1905 anyway.

Scandinavia? Expanding into Norway and Sweden fulfills no great Russian interest, would scare the wrong sort of people, and would not increase overall population much.
The Americas are hard to get large numbers of settlers to before the trans-Siberian railway gets in, which also makes American territories hard to defend.
With an early POD such as no Manchu dynasty or perhaps an earlier arrival of Russia at the Pacific, Manchuria might be snagged before it fills up with Chinese, but whether the addition of a mostly empty Manchuria strengthens Russia more than it is weakened by the loss of tens of millions of at least potentially assimilable Belorussians and Ukrainians, I dunno.
Bruce
[1] Not that many "UK of Poland-Hungary" wanks out there, at least when it comes to maps.