You could potentially replace the CD-ROM drive with a generic one; however, a small modification will be required for it to work. You will need to bridge two pins on the connector with some solder (
guide).
Another option would be to install the hard disk drive into another Macintosh computer, set up the operating system there, and then return it to the PowerBook.
I am personally unfamiliar with this model, so I'm not sure if it can boot from USB through OpenFirmware, but that is certainly something you can try as well.