First off, you would *never* save anything you found off to local harddrives. Doing so would compromise the drive by altering the state you fond it in, quite unecessarily. This violates the first rule you should be observing when conducting any type of forensics work.
Sure, you may know that nothing you did affected the evidence in any way, but you're not going to be able to prove that in court, whether that should be either a civil lawsuit or a criminal trial.
You could instead use netcat to pipe the results out to a computer elsewhere on the network, or mount a USB stick or flash drive as you suggested. It's not at all difficult, and the methods used to do this would be no different than on any other hard drive based system.
Or the drive could be mounted in a forensics workstation and all data saved to a separate drive.
So yes, you could still access your local harddrives. A forensics CD would be rather pointless if you couldn't. What would there be to investigate? But, to actually do so would be a *bad* idea, unless you had another local hard drive to save it to.