Honestly, I think the only 'safe' way to do it is to buy a second
    hard drive, install a fresh DragonFly on it, boot it with the old
    drive as drive #2, and copy over the bits and pieces of data you
    want to retain.

    It isn't so much the OS core that I'm worried about, but all the ports
    applications one might have.  You really want to scrap any ports stuff
    and get the same setup with pkgsrc, then copy just the operational
    data over.  That isn't something an installer can do for you.

						-Matt