The Allegheny runs through town, wild brookies in the far headwaters, wild browns + stockies just above town, wild browns + wild brookies + stockies below the culvert, shading to smallmouth/musky water as you go downstream.
Mill Creek also runs into the Allegheny right in town. Wild browns.
Freeman Run, which runs through Austin, has wild brookies and browns as well as a stocked stream.
After that, I'll just list drainages, as there's too many streams to mention. These main branches can be worthwhile, but every trib you'll find most likely has wild fish, brookies or browns + brookies, and many are stocked as well. Potter Cty has more wild trout streams than any other county in the state, it literally is basically every single stream.
To the SW, there's the Allegheny Portage Creek and Sinnemahoning Portage Creek. Both are fine drainages with numerous tribs that hold wild trout.
To your south, you have the First Fork and the East Fork of the Sinnemahoning. Not sure how either of them will fishin in the heat of the summer (East Fork probably better than First Fork), but both have numerous tribs that are excellent.
To your SE, you have the Kettle drainage, but you're going nearly an hour for that. This drainage includes the Cross and Hammersley Forks.
To your east you have the upper Pine drainage, again, I don't think any of its tribs are bad, but the main stem may or may not be borderline temperature wise in mid-summer. Just a little farther and you're on mid-Pine, which includes Slate and Cedar Runs, as well as many others.
To the NW, the Oswayo, to the NE, the Genessee. Both fine drainages.
I mean, honestly, if your name implies that you like wild brookie fishin, pick a blue line on a map and go, you have hundreds of excellent choices. Basically any stream of that size is gonna hold wild trout. Browns seem to dominate north of town, where the places south hold brookies or a mix of brookies and browns.