Do you use knoppix much? I've got some predictable tech questions in a couple of days. I want to play with it for a while and get a feel of it, and see what I can figure out. I think I'm lacking the root password, though.
While I don't use Knoppix a whole lot, I could probably figure out your questions. The root password for Knoppix doesn't exist. Just type "su" at the prompt and you'll be the root user, I believe. If that doesn't work, let me know and I'll figure it out for you.
As far as lightweight Window managers are concerned, FC3 (I believe) also has XFce which is a nice, lightweight WM. I've heard good things about it.
To set the root password on Knoppix, start up a command line console, get root privileges by entering "su -l" then enter "passwd" and set it to anything you like.