Tributaries are probably the BEST place to be in the midsummer. They will generally be cooler, and you'll probably have better luck. The key is, you need to find water that is under 70 degrees.

As for bait, whole red worms, or half nightcrawlers fished on a size 8 hook will generally do quite well. Keep them along the bottom, but don't pin it to the bottom. A size 0 Mepp's Aglia will also do the trick.

the above suggestions for bait are both very good, another key is to see them before they see you. always stay downstream from the trout and stay low to the ground. also they are less aggressive when tepmeratures get high so keep your crawler barely moving along the bottom. where in PA are you headin? i'm from western PA so i might be able to give some good spots.

I don't know if there are brown trout where you are going, but they are most active and least bothered by the warm summer water. Fish topwater or use a small floating minnow plug or worm retrieved slow and jerky near the surface in the late evening and at night. That's when you'll catch the biggest brown of your life.

Im in north central PA and the Rebel Craw is doing very well. You way also want to try a small Rooster Tail in the bee pattern.