Is cost an option?
You say you have a Hard Drive, so it must be on a Zorro SCSI card or you might be really lucky and have a Buddha IDE card. Either way, a SCSI card might have a connector on the back to allow external devices (Good luck finding an external SCSI CD ROM, buy eBay might work!). Whether you have IDE or SCSI on the card, you should be able to get an internal CD ROM drive to go in the 5.25" bay.
If you have some spare cash, I'd recommend:
CPU card 68020 or better to allow you to run OS3.9 (and make use of a USB card if one becomes available from Jens) with some extra RAM and KS3.1 (onboard SCSI would be a bonus).
A SCSI (or IDE) CF Card Reader. Use it as a hard drive or to transfer files from a PC.
Just to give you an idea of what I have in my A2000:
68040 CPU with 32MB RAM and SCSI
Kickstart 3.1 running ClassicWB (OS3.9 based)
80MB SCSI Hard Drive (backup)
SCSI card reader in 3.5" Bay
Buddha IDE Controller with 4GB CF Card as boot drive (internal) and CD ROM in 5.25" Bay
Deneb USB Card with Ethernet dongle
Scan Doubler/Flicker Fixer
Cybervision 3D Graphics Card
A lot of the parts came off eBay and it can certainly hold its own against my other miggies (except for AGA games).
