Recommendations on Direction of Travel

[MkBeaudry]

I’m planning to travel in the spring and summer of 2025 in the area of the Caspian Sea to the North Pacific Ocean. (was in Georgia and Azerbaijan last year, so not that area) Included is Mongolia and S. Korea.
So far, I’m solo and my type of travel will be driver/ guide, trains, & some tours.

From what I’m reading, it seems most folks move from west to east.
Is this the recommended path? Is the travel easier for some reason this direction?
Does this mean driver/ guides would be more available traveling the opposite direction?

Any feedback and advice would be appreciated
Mark