What would motivate Imperial Russia to continue building colonies down the Pacific Coast and establish a Russian America?
The problem in OTL boiled down to competition. The Hudson Bay Company took too much profit from the Russian trappers and with claims on various parts of the West Coast from Britain to America to Mexico the colonies became unsustainable, leading to Russia's sale of Alaska.
Let's say for the purposes of this challenge that we have a version of the USA dominated by Whig-style policies opposed to excessive expansion. What could lead to a victory for Russian interests on the Pacific over the HBC?
One of my thoughts was an earlier Gold Rush in Russian California, perhaps in the 1830's. Maybe this motivates Russia to spread South to avoid British competition for furs and establish a new trade good to ship from the New World.
I also know that Russia was unable to trade from the West Coast to the Canton (Chinese) market, but I don't know why. Can anyone shed a little light on this? If the Chinese market was open to Russia trade, would this motivate Russia towards further Pacific expansion?
What could make the Great Game expand to the Pacific Coast?