I tried this with a friend 2 years ago...my memory isn't super clear, so I can't give real specific details, but here is what I remember from my experience (not sure what the flow was, but I'll guess it was lower than what it is now). I would say II/III is pretty fair, probably trending moreso to the II side than the III side. One really low footbridge at one point, not too too far from the tunnel. At higher (current) flows, the thing could be submerged, I suppose. Other various manmande obstacles...at that flow, low-risk diversions, culverts that you could just boat through, etc. ... at these higher flows, dunno. First homeowner we encountered along the river said we were the first he'd ever seen trying to boat the section, but didn't seem to have any problem with our presence. Definitely multiple barb wire fences. Got to be a real pain in the arse, but we'd set up for a pretty long run, so we were committed. One barb wire portage forced us to walk a decent little ways, climb a couple fences...with two other homeowners watching with amazement, but again with no apparent issue. Then on yet another barb wire portage on an open ranch that can be seen from 285 (probably a little short of the halfway point between the tunnel and Bailey)...the landowner, who we'll call "Farmer Dan", came screaming down the pasture in his golf cart, outfitted with shotgun. He was actually pretty cordial, but was not ok with our trespassing, which he insisted was the case even if we weren't touching the bed, banks, etc. (which we were having to do because of all the barbed wire). He said Denver water made him put in all the fences and that we would find many more yet to come (he was probably right). He offered (with a certain insistence) to drive us back to our vehicles, which was really ok with us, since it wasn't panning out to be all that enjoyable with all the portaging. It was an adventure, nonetheless. If you go, make sure to say hello to Dan for me.