Is there a way to treat the CD only as a kernel loader?

[cvevans]

For Knoppix 5+ it is easy:
copy the CD or DVD to any partition on your HD (NOT the .iso)
(for Knop6 CD it MUST not be an ext* - FAT32 works)
Remaster the CD or DVD to a CD,
delete the KNOPPIX/KNOPPIX*

now booting the CD will find the HD copy.
after boot you can remove the CD.

You can also copy the CD or DVD to a USB drive,
but beware of crashes when plugging another USB device -
if possible, plug a powered USB hub before booting;
after booting, only plug into the powered USB hub.