I'm interested in the idea of creating a 'China' in the West and, since there are only two major civilizations in the West at the time China was just waking up, Egypt and Mesopotamia, I have to use one of them. Since Mesopotamia isn't really ideally positioned for unity, we're left with Egypt.
Now, one of the things which made China China was its vast size. It absolutely dominates East Asia. Even though non-Chinese civilizations arose, none of them could possibly compete in the long run with the Han Behemoth. Contributing to this vast size is the fact that China contains not one but two of the most fertile river valleys on the planet. While there were plenty of Chinese people living in the areas around the river valleys, for a very long time the vast majority of the population lived within them.
So, in the West we've got a somewhat similar situation with the Nile. It was and still is very fertile and has always supported a very large civilization. However, as time went by in history, powers which could expand outside the, ultimately, limited area of the Nile surpassed Egypt and, by the time of the Roman Empire, Egypt had lost its independence and would stay a conquered entity for almost a thousand years.
So, the lynchpin, I believe, is to create another large, fertile river valley for the Egyptians to expand into, further increasing their population base and making it much more of a 'China' analogue. Now, the Nile itself is an extremely long river, stretching from Lake Victoria as it does. Might a similar body of water somewhere to the west of Lake Victoria create another continent spanning river?