I have a Pentax K5, and it seems to me, your tone-look is pretty much what I get with my images. It looks like you have the camera set on natural tone rendition. There is also a bright tone rendition. I had the same reaction when I saw my first digital images from the Pentax K10. They looked somewhat flatter than the reality I remembered. My suggestion, if you do not want to alter the image in post processing, is to try and vary the sharpness, colour and/or brightness levels, as well as the tone setting and see if you like it better or that it more closely resembles what you saw. And if you are in doubt, shoot a duplicate at the default settings and then compare them. I only shoot jpegs, so if you are shooting raw, this could alter what I just wrote.
By the way, I like the images, especially the first. I am reasonably certain that the light in the first image should appear brighter as I have similar images with this type of light. Not a lot more, but definitely more, and with a little more luminosity. I had to adjust mine a bit and one could say this is just me being subjective and trying to improve the image, but that is my feeling. Also, I am somewhat taken aback by the almost square format of the 4X5. For me it takes a little getting used to and appears to give the foreground more dominance in the balance of the image.