I can answer this for you.
Your best bet would be to go to the Construction Bank of China. Although I have never personally done it, I am told by a reliable source that this particular bank supports international bank routing numbers. They should be able to transfer the money directly into your American bank account. There will be a small fee.
Another option would be to send the money to yourself via Western Union, available in most China Post offices, but you would first have to change the currency to U.S. dollars. The easiest way is to give the money to a Chinese national and have him or her do it for you. Western Union charges a fee of $50.00 per $2,000.
If you decide to carry cash, I would convert the renminbi into dollars in China first—you'll get the best exchange rate that way. According to the State Administration for Foreign Exchange, you can carry up to $5,000 in or out of China without declaring it with China customs.