I did have to look that one up.  Went down the river in May 2000, so it was a long tome ago - but I didn't remember running any real rapids?  The portage on the island is marked on my Fisher map - it says 4 rods and has all of two red dots on the island (my notes said 10 rods) -  vague memories started coalescing, and I finally did remember stopping on the island - I don't think the landing was obvious, just take out on a flattish rock.  we went down the river from the lake to the Quetico river, and up that back to B-house.

Just thought I'd throw that info out there, as I suspect that you will go back to do that trip again, doing the section of river you missed this time.  The river below LLC was nice - good current and some rock dodging, but not too difficult.  only other portage I recall was around Ivy Falls.  At that time of year, there were a lot of sturgeon in the river - you'd float over a pod of 6 or 8 big fish every so often.