Troop marching distances are calculated "as the crow flies" (and you can calculate a distance fairly exactly by subtracting coordinates and using the Pythagoras Theorem). Troops march diagonally, making it difficult to figure out the timing.
Since there are a variety of variables that influence your troops' 'base' timing, I have created an Excel spreadsheet to accurately estimate the marching speed of any troop to any co-ordinate* providing you march a militiaman vertically or horizontally 20 squares or so to get your 'base marching time'. Download Here
- the KoC map 'wraps around' at the 0 and 749 X/Y boundaries. This spreadsheet won't account for that. However, you can probably tweak it to work if this is an issue for you.
Enjoy (Darkfeather, Proph3cy)