You're right, KN5000 is a wonderful keyboard. Even today, and the features as i.e. composer and panelmemories and the very easy operation system, what other brand come close to that?
EMC Styleworks is pretty expensive, and you'll see the prices at EMC's website
Styleworks is a nice tool, but it don't sound like a "wonder has happened" after a raw convert. As mentioned above, it takes a lot of work, you have to tweak and adjust a lot, swap sounds etc. to make it sound any good.
KN5000 package contains a convert disk that is a simplified version that works only stright at the KN, but Styleworks is a PC software and have much more options.
Regarding the KN diskettes, if your PC don't have a floppydrive, you can by a cheep external to plug into the PC.