It’ll depend on what part of the lake you want to fish. The best easy to get to fishing could well be from Two Harbors to the Silver Bay area at that time. You’ll find salmon and lake trout all the way thru this general area but one place or the other will seem to have more salmon than trout and vice versa. I target lake trout at this time in the Two Harbors area while a lot of the locals are heading up the shore looking for salmon.
August is when I see schools of walleye running up the shore from the south shore too. They are a chance fish though, but if they are around whatever you are dragging for trout or salmon will catch them as well if the baits run thru the school. Check closer to shore for loose schools of fish. They can be either herring or waldos.
About the herring….if you get a fish or two, gut and gill them pronto and put them on ice. When you get home you can finish by filleting the meat like a walleye. Dredge in seasoned flour and fry in an oil/butter blend on medium heat. Herring cook super fast and the translucent meat while raw stays that way in part when fully cooked. When the coating is browned nicely, the fish is done. Herring are a treat from the big lake and in some eating establishments along the shore they are considered a delicacy.
If it were me I’d do the Two Harbors launch and stay in that general area while trolling both towards Silver Bay and/or down towards Knife River/Duluth. There is some amazing structure in the Two Harbors area that can provide some super trout fishing by trolling or jigging. You can leave the boards and mast at home at this time of the year if you carry some lead line rigs and dipsies as well as downriggers.