15Hours Layover in PEK coming back to USA

Your itinerary, if you have mentioned all your stops, is definitely eligible for 24 hour visa free transit in Beijing.

As far as your wish to exit the airport is concerned, you have two options:

- You can apply for 24 hour free entry permit upon your landing in Beijing. This option is totally free and you are supposed to bring a confirmation of your accommodation booking and the confirmation of your tour at the moment of your application. So, have these confirmations in hard copy. Anyway, you should be aware that the issuing of entry permit is not a passenger's right, but it depends entirely upon immigration authorities discretion. The practice has shown that the largest majority of passengers, having with them a booking or tour confirmation in hard copy, are granted an entry permit. Your chances for that are really very, very good.

- You can apply in advance for Chinese transit (G) visa in advance at relevant Chinese visa issuing institution. With this visa, you will be definitely allowed to exit the airport.

Now, when you know your options and circumstances, it's up to you to decide.