I read a book once about the face-off between the Japanese and Americans in the Aleutian Islands during WW II. We hastily built what's now the Alaskan Highway (pretty much connecting airports from Dawson Creek to Fort Nelson, Watson Lake, Whitehorse, Dawson Creek, and Fairbanks).

The winds and weather were so bad, the US and Japanese ships/planes seldom engaged. The Japanese took Attu & Kiska Islands during the Midway Battle in '42, and they were eventually liberated in '43 after pretty much a stalemate.

In conclusion, I wonder what could be gained by the Russians in an invasion?...hard to conduct, little strategic value, and surely fierce resistance. I doubt they could afford such military adventurism.