From the Princess website:
Pier Address - Diamond Princess Daikoku Pier Cruise Terminal13 Daikoku-futo, Tsurumi Ward, Yokohama
I read that the Diamond is too tall to sail under the bridge which is necessary to access any of the other piers hence the docking at the Daikoku Pier.
I'm not terribly confident that Princess is going to provide a shuttle so I'm happy to hear that there is a regular bus that will be available to us. Thanks @BruceMuzz!!