OK, here is what I came up with.
First I created a levels adjustment layer. The histogram looked pretty good already, but I dragged the end sliders in from either end just a little bit. I think I moved the white point (right side) slider a little more.
Then I created a Curves adjustment layer and made a slight S-curve to increase mid-range contrast.
Command Primer
Then I created a hue/saturation adjustment layer and boosted the master saturation. I also boosted the blue saturation and tweaked the hue by a point or two. I took the yellow saturation -2 down as well. I'm not working on a calibrated screen here, so take that for what it's worth.
*edit* I maybe should have toned down the cyan, as the sky near the horizon looks really cyan...but oh well.
I'm working on an older version of Photoshop here, otherwise I might have tried to adjust the Vibrance, which is a cool feature of the new versions. It's like saturation but also different.
Next I used the dodge tool to lighten the barn a little bit. Then I used the burn tool to darken the edges (vignette) but also to darken the sky and other select parts of the image as I saw fit. I do this with a very low opacity and treat it like I'm freehand sketching, with many loose strokes.
On a larger image, before printing, I might also take some time to selectively sharpen parts of the image.