Can't help you with the fish locating but I will say enjoy the time with your son up there even if you don't do well fishing. I lost my dad about 3 weeks ago, and just reading Dog Lake brought a flood of old memories for me.
Had to be 30 years ago now, I went up there with my dad, uncle and a bunch of my dads buddies. It was my first time fishing in Canada and I remember going through the channel from the lodge we stayed at, Island View I think it was, to Bay 57 and having to sit on bow and call out car sized rocks as we motored through. Scared the shat out of me because I kept thinking if we hit one we are going to sink and no one will ever find us, granted I was 9 at the the time so it was a real fear. Being the youngest of the group I was picked on more then my fair share, but those times I wouldn't trade for anything now.
FWIW, It wasn't at Dog Lake but another lodge we went to years ago and the guide there said that if you wanted to catch smallmouth the thing to do was to put a piece of nightcrawler on a hook and put a couple of split shots above it and cast as close to rock ledges or cliffs and just let it drop down. The smallmouth sit along those edges and will wait for things to fall into the water. It worked back then, safe bet that it will today.
Good luck up there.