There is a method to export installed scripts, plugins (e.g. Red Giant Trapcode Particular) and preferences (e.g. workspace) from After Effects CC to After Effects CC 2014?
Scripts can be in any folder so you can just create an alias or simply copy and paste them to a new folder.
Animation presets for 3Rd party effects and Plug-ins installed by installers like Red Giant should be re-installed and CC 14 selected from the list. The updated Red Giant installer will do this and you should do it that way because some compatibility problems were fixed in the latest builds from Red Giant and other 3rd party manufacturers. Other plug-ins may be copied and pasted or an alias used to bring them over. Preferences migrated from previous versions in the Preferences > General page at the bottom of the screen.