On location you cannot really judge exposure or skin tones with the on camera screens.
You really need to use a Tablet PC with a calibrated monitor in a black laptop tent/viewing station.
I also use a black cape to cover my head and shoulders.
However exposure can be checked quite well on the histogram and skin tone is best when doing the correct
white balancing.
You can always use a really nice and compact Samsung Slate PC. It's a tablet that runs windows and you can calibrate the screen with
screen calibrators. Also the screen is really high quality. Gives the very best pro screens a run for the money. All you will have to do is
use your memory card to move the files over. It's actually quicker then you would think. It has a very fast processor and runs lightroom very well.
Lightroom is also very touch screen friendly. Also on location it can often be more practical to use a memory card than tethering.
The wide screen works nicely with the 5x4 aspect ratio of MF so you can view the whole image and still have room for controls on the side.