If my knee holds out, I'm planning on running the Midwinter Marathon too.
http://www.afstandmeten.nl/index.php?id=1839 (the little man thingy may be useful)
and
www.youtube.com/watch?v=K_iOhoRBfQQ
That may give you a better idea of the course.
If it's icey, the paths and raods should be cleared.
http://tinyurl.com/dxlybgf was this year
It was fairly cold this year, but it was still run. The organization took some special measures. They shortened the permited time to 4.5 hours (I think also partly for the benefit of the volunteers). The 27.5 km course follows the same route, so if you didn't reach the point where they split at a certain time, you were made to only run the 27.5 km course. There was also a number of heated tents along the course if you got too cold.
Edited: 13/11/2012 at 15:46