Even if you manage to transfer your library, the storage position/path to your media files will definitely change. Unless you are willing to edit your Plex database by hand, this will result in a rather lengthy redownload/refresh of metadata.
So if you have your file and folder naming in order and your embedded music metadata too, then it is less work to just recreate the libraries.
Ok, I’m putting all this in stasis until I map out a NAS solution that will handle everything. Still waiting on SiliconDust to finish their DVR option, so I have at least a few more months of planning ahead of me…