Question on visiting visa free

Hi,

We are arriving from Tokyo (Japan) en route to Beijing. However, we have an overnight 21-hour layover in Shanghai on the way to Beijing. From Beijing, we are leaving to visit Pyongyang (North Korea) on a separate ticket the next day via a different airline. All of this means we will be in China for a total of 48 hours in total. Are we allowed to leave the airport freely to see Shanghai while we are there and then do the same in Beijing? Or will we be denied this privelege?