@Hewey and I paddled from Bamber several years back. As German said, it is tough going. Definitely don't do it in a canoe. The channel is anastomosing, shallow, and chock-full of fallen tree trunks and limbs.
Guy and all,
That map misplaced the forge a bit. Here was the exact location:
The two race ways are still visible, along with the dam and a pile of forge slag.