PC to Amiga 4000 file transfer

Hey all,
Finally got the 4000 all ready to be reassembled, but I'm not doing it quite yet, as I want to find a way to easily transfer files between my PC and it. On my 1200, I used the PCMCIA slot and a CF card, and that worked great! The 4000 doesn't have that, so the way I've been putting files on it is to take the HDD, attach it to my PC, mount it in WinUAE and copy files to the emulated Amiga using the real HDD. Works, but not ideal.
It has a modern IDE CD drive, so there's always the option of using CDs, and maybe CD-RW if I'm lucky? Is there another way to transfer files? Some super simple serial thing? USB would be awesome, but the Subway USB controller costs $140 USD or something, and it needs another $100+ part to work on the 4000.
Finally got the 4000 all ready to be reassembled, but I'm not doing it quite yet, as I want to find a way to easily transfer files between my PC and it. On my 1200, I used the PCMCIA slot and a CF card, and that worked great! The 4000 doesn't have that, so the way I've been putting files on it is to take the HDD, attach it to my PC, mount it in WinUAE and copy files to the emulated Amiga using the real HDD. Works, but not ideal.
It has a modern IDE CD drive, so there's always the option of using CDs, and maybe CD-RW if I'm lucky? Is there another way to transfer files? Some super simple serial thing? USB would be awesome, but the Subway USB controller costs $140 USD or something, and it needs another $100+ part to work on the 4000.