The water level at the starting Yorkville gauge was at 13'10", with a CFPS of 1500. Nearby the end is the Dayton dam, and it was at 6'10", and flow was at 1800 CFPS. The water level for our trip a dash lower than average. We scraped up on sandbars a few more times than typical. The current was also fairly slow. I've seen worse depths and flows, but this was near the bottom for a trip that I'd enjoy doing. Much lower than that, and it'd be really annoying.
We put in at Yorkville, just after the dam. No portage that way. You can put in before, but then you are only doing a few miles before having to get out and move gear. Not worth it to me.