If you manage to find a application that can transfer you're playlists, the things described below can be more simplified. But if you got a fairly good naming system and tag data on you're files this can also be done pretty fast manually.
How much of this do you have in some kind of tag? As I can see you use the following: "Audio type" (music & audio books), Artist, Band, Album, Name, Track, Audio Book name (name) or Series, prefix numbers (track and total tracks).
If all, or most of this is either represented in tags, the file name it self or can be separated with a directory structure, you'll have a pretty easy job of importing it and get the same system as you use today. Not with playlists, but a well organized library with tags. Most Playlists CAN be created after this have been done, but would bring little to no functionality.
One example: Your Audio books and Music are separated by different folders. You have the Artist/Band, Album, name and series tag in iTunes.
- Start off by importing the structure with Audio Books. Set Media Sub Type to Audiobooks. It's now separated from music when you import that. If you're lucky enough to have both the number prefixes, author and series/name in the file names, use Get tags from filenames and fill them all in. You'll have to make a custom field with Author first. If you're missing Author you might have to sort the tracks on file path and set the Authors accordingly. This might take some time depending on the amount on authors, but should be fairly doable. If the series/name data is stored in series tag from iTunes, it will show up in MC as well. Total track numbers can probably be found with a Expression field, but I don't know how.
- Then import the music structure. If all correct fields have been used in iTunes, there should be little you need to do here.
It all depends on how well you have done the tagging and file renaming from the start really. Therefore I might be really off here. It's just a "in the best case" suggestion I guess.
