Dudes,
I have to weigh in now because I feel there's some mis-information getting posted.
First, Cruise gulley is 4th class (high exposure, hands and feet scrambling, rope is optional), but use caution when wet. I've hiked out after a climbing day gone bad in a rainstorm. My borther has hiked it when it was dry and he doesn't climb and doesn't enjoy heights either. If it was an emergency (lost boats, urgency, etc.) I would not hesitate a bit to send someone up Cruise gulley because going to SOB would add at least another 1/2 hour in portage, plus a 1/2 hour longer hike, and you need a boat for the ferries.
Secondly, while fishing last fall, when the water level was 300, I was able to cross from SOB to the other side (upto the first pool you ferry across to the S. Side) and it was sketchy getting back. I had to build a ramp with driftwood to do it. Ankle-snapper type stuff. Definitely, the way to portage with a kayak is: waterfall, walk north side, ferry to south side, walk, ferry back to north side. And on both walks stay as close to the wall (far from the river) as possible for the easiest trail.