Holding a US passport and transiting Beijing with a 7 hours layover before my connection.

I'm flying Air China from Bangkok to Los Angeles with a 7 hour layover in Beijing before my connecting flight. I'm transiting without a Chinese Visa. Can I use the 72 hour free transit or will I be able to roam the airport freely. When transiting, some countries put you in a room with no access to any of the airport shops, restaurants etc. You are escorted to your connecting flight once boarding starts. Does Beijing handle their "transit without a visa" in that manner?