booting knoppix from an external drive on an old laptop

Hi all,

My laptop is old enough that it doesn't know anything about booting from USB. Can I use the tohd cheat so that I can just pop my knoppix onto my external drive, initially boot it using the CD and then use the /fromhd to have it continue on.

If that works, can I install/remove packages etc, create files and so on without the need for creating the home location.

Apologies if this has been asked before - I've googled this a bit but I can't seem to get a definitive answer.
Howto's / URLs would be greatly appreciated.

Cheers