I don't fish around Ligonier a whole lot anymore, but have taken my two trout bum sons there a few times in the past couple of years. The Loyalhanna DHALO is pretty nice water. Although a bigger stream, that section is pretty manageable and has some different types of water to fish. My 7 year old can fish several spots comfortably.
Mill Creek - a trib of the Hanna - is some pretty nice water too, and smaller. Linn Run is definitely small water with lots of character, and I imagine since its last stocking was weeks ago, there would be very little angler traffic there.
If you have time for a hike and want some brook trout, check out the Game Commission's website for Game Lands maps. Lots of blue lines in the area to explore with some gorgeous water.