The Pentax K5 and 35mm lens area good choice. In your case, I would also consider a full-frame camera, this would allow a more faithfull reproduction of colour and smoother tonal gradations.
I use the Canon EOS 6D, which is realtively cheap. In your case, you could get the 50mm macro lens (it is an old lens, but very good, with a flat field of view and no distortion), or the 50mm macro lens from Zeiss (which is expensive). If you opt for two separate lenses, then I would recommend the Canon 40mm pancake lens (which makes a really small package with the 6D) for your normal field of view lens.
The Canon 6D has inbuilt GPS and Wifi. The GPS could be helpful to you, to document your locations easily.