If you get a Deneb you'll be able to use an uber cheap PC USB network adapter card.
But you really don't need USB or a network card to get everything you could want from a classic Amiga.
While the panel adapter IDE->CF is not hot-swap it makes it so much easier to get data from the PC. Plus if you have a hard drive installed in your A4000 with the FAT95
filesystem drivers then you can use a FAT32 formatted card making it even easier to transfer files between the two systems.