If you copy the applicable files in C:Users(your name)AppDataRoamingPoser Pro11 to C:Users(your name)AppDataRoamingPoser12 you can just move all those links right over. Runtimes are listed in LibraryPrefs.xml.

You should probably also edit it to include the new folders added for 12. Although frankly it starts getting ridiculous when each version installs its own folder containing almost all of the content from all the previous versions.

Note these are hidden folders. Click View on the ribbon and pick the option to show hidden files in order to see them.