Nice photos and I agree regarding the post processing. With my current lenses, in auto and semi-auto modes, my K-r consistently shoots images just a hair on the under-exposed side. I rarely get an over-exposed image, which is wonderful . I think it is very difficult to correct an over-exposed image in PP; at least I haven't figured out how to do it well .
Since i got Adobe Elements, all I need to do with a photo like the ones you have here is run them through Smart Fix in Elements. One click and it seems to brighten them up just right. I usually have to do little else.
I like your third image the best.