That's a good stretch of stream - in fact, I've fished that section probably more than any other part of it. It does seem to bend away from the trail that goes past the water tower, so there's a longer stretch of stream there than you think. The Low Gap trail is a bit confusing, because you can take the one path that goes by the water tower, or you could take the portion that comes out of the nature trail area - that part is on the left side of the stream (as you're going uphill)...but, it is separated from the stream by several yards and a lot of thick growth. Eventually, the two parts of the trail meet at a crossing upstream, and then Low Gap continues up the mountain.
We also ended up fishing a section far downstream of the campground (in fact, it was right past the sign that states that it is 1.7 miles to the campground), in one of the pullouts. I expected rainbows, but in a few minutes of fishing, we ended up with 5 brookies....it seems like they are moving downstream on a couple of the places where I fish - a good sign, IMO.