If your editing software allows the use of masking, you could try adding just a fraction more highlight brightness, but partially mask the effect over the sky to tone down any resulting over exposure.
This is my version, and bear in mind it is an interpretation, and may not jive with your initial vision, They way I see it there are three main elements in the image: the sunset colour, the light on the hill tops and the texture of the fields (folds and crop rows)
This was all done in Aperture with NIK Vivesia plug so you will have to go with the intent as the mechanics may not translate to another program.
I made the blue sky and red horizon more saturated and then darkened the entire sky. I made the field a little cooler as if I saturated the colour it would be a nasty orange (the light from the setting sun is really red and makes the tan field more red than desired when worked with) Saturated that colour a bit and then lightened it. Then increased the structure (a slider in NIK that enhances the edge effect) and increased the contrast in the field to make the folds of the hills and the crop rows more prominent. Then an S curve on the entire image to make it even more contrasty. Finally a bit of sharpening to again bring out structure.
I like it Trevor, and thank you for the effort and explanation.
I took a slightly different approach, giving the fields a softer appearance. Yet, what's fascinating about the Palouse area is what you have highlighted, and that is the rolling textures within the fields. I've seen both approaches, and what you did is fantastic
Beautiful!!