The trail (mentioned) along the river above Chatterton Falls is on the South Side - that is, to the right as you look at the falls.  It starts in a campsite, as close to the falls as you can get.  It is a nice, worthwhile hike up an old, unused portage.

The actual portage to Chatterton Lake is on the North side of the falls.  Usually good fishing near the falls, and a 1/4 mile or so above the outlet of Russell - there is good current there in shallow water.

In June, it is 50/50 odds that you could paddle all the way up the outlet (the river between Sturgeon and Russell) - if the water is too high, there is a portage on the right side, not really obvious - it goes up a slabby rock and around the rapid at the top.
Otherwise, eddy hopping from side to side works to get you up the river - no matter what, don't get turned sideways to the current.