I am an Australian citizen, flying from Sydney to take a cruise starting from Shanghai

Using the 144hours exemption (or any other applicable exemption), will I be allowed to leave Shanghai Pu Dong Airport & travel to the shipping terminal to board the Celebrity Millenium?
The ship then starts the cruise that evening and then has 2 sea days before reaching Beijing (Tianjin). The ship stays in Beijing for 3 days, arriving at 6am on the 1st day & departing at 5pm on the 3rd day. The following day will be sea day and then the ship goes to Seoul.
Are there any necessary documents that must be presented and does the 144hours exemption apply in this scenario?