First of all, I just want to make the observation that your image clearly demonstrates the fact that the Pentax 18-55 mm kit lens is an outstanding lens; I have two, one is the weatherproof version.
As for this particular image, the first thing that hit me was the common rust color in the bridge and the oranges in the autumn colors. After that I noted the contrasts of the strong lines of the bridge, which also serves as leading lines into the center of the image, against the fractal leaves and the amorphous clouds which are, in turn, reflected in the ripples of the river. And the vertical reflections in the river also serve as lines that lead into the center of the image.
So in summary, this is an absorbing image for me; there's a lot to see in it.
As for the K-5, I had two K100D Super bodies prior to getting my K-5, and while I really like the K100D's, I love the K-5 and I'm sure you will too. As we Pentaxians say when trying to describe it to Canonites or Nikonians, "It's like the D7000; only better."