After long discussions on the MacTeX mailing list, and thanks to much work of many contributors, I can finally announce the CJK font integration script for GhostScript. While far from perfect, especially because GhostScript enjoys crashing on several Chinese and Korean fonts, it allows users to make the CJK fonts they have on their system automatically available for GhostScript.
The script and detailed explanation are available on the dedicated page CJK fonts and GhostScript integration (also under the Software menu above). I would be happy to see feedback from a wide variety of users, especially Chinese and Korean, where we have the least experience.
Thanks, and enjoy.