Simply buy the BTC, and when you have access to the BTC, simply withdraw the coins immediately to the US exchange. If you're going to send from an exchange, chances are, the withdrawal fees are going to be slightly on the higher side by default as to not take you too long to receive the coins.
How long would above step take? What if btc drop significantly like 10% during this process? It doesn't seem impossible for this scenario to happen.
In my experience it takes 2 or 3 hours to get enough confirmations for a single transaction to be considered accepted, depending on how many blocks are found at that time. So buying the BTC from China will be one transaction and sending it to an exchange address in the US will be another and the whole process should take about 4-6 hours. So far, in that timeframe, I haven't seen bitcoin's price move by more than a few hundred dollars.