I've traveled the route out the north end of Sarah twice (just last week for the second time) it is beautiful and I would be willing to bet on good walleye fishing in Irene and the unnamed lakes around her (there are somewhat primitive portages to a few). Irene is clear water but I saw lots of good structure. On the portages between Irene and Kahshahpiwi I've found the tallest white pines I've ever seen, damn near redwood in their length.