It may be relatively easy for Russia to re-route its oil trade stream towards Asia, primarily, China, although this would mean lower prices and higher delivery costs. I am not so sure about Russian natural gas, though.

I agree that any restrictions limiting use of the global financial and banking system (which I mentioned as similar to the sanctions Iran is subject to), would immediately affect Russia's industries exposed to foreign trade, and indirectly all others, including consumer market. Russia is much less self-sufficient and far more integrated into the global economy than the USSR ever was.

As for deploying NATO contingent in Ukraine, I see multiple issues with this. First of all, the alliance doesn't have a mandate for the presence of its troops in the country. Setting up a legal basis for this may take significant amount of time, and I'm not sure all member countries will get on board. Second, what government would be willing to commit its troops that are, for all intents and purposes, unable to even defend themselves?

Besides, Russian military would make its move into Ukraine at first signs of NATO potentially coming in there.