As far as I know independent travel in North Korea is not allowed. Movement is restricted to only guided tours – which, may or may not be, something that helps/prevents you from blending in.

All things aside, since you can’t blend your physical stature, make sure you read up on how to dress, know the political taboos, and only interact with your tour guide and members of the tour. Police, government officials, etc. – I’d keep clear of them if possible.

Here’s my quick guide to visiting North Korea:
http://www.foxnomad.com/2008/02/12/the-quick-guide-to-visiting-north-korea/

Let me know if that’s useful, and would *love* to hear about your trip when you get back. Feel free to contact me if your interested in posting it here or have some tips for the rest of us.