Here you go!
Map movement:
Positively affects map speed:
Some low level perks in the Scouting tree, have a companion in your party fill that role by designating them as Scout if they have a decent skill in it because it takes forever to raise with minimal benefits.
Personal movement speed whether mounted or on foot and the associated stats athletics/riding affect your base party move speed (needs testing)
Cavalry in party and having horses for your foot soldiers to ride increases map movement tremendously, foot soldiers riding horses only recieve about 80% (needs testing) of the movement bonus that cavalry provides.
Negatively affects map speed:
Holding prisoners and higher % of your max weight carried (small penalty)
Lots of wounded soldiers (moderate penalty, wounded soldiers don't ride horses so it can increase your herd size debuff as well)
Herding (dynamic penalty), and Disorganised Army debuffs (more below)
Hauling more weight or prisoners than you can manage (Very harsh penalty the more you go over your limit)
Herding debuff:
Reduces movement speed if you have a lack of soldiers to herd your sheep/pigs/cows/mules/horses, it can be reduced or nullified by having a decent ratio of soldiers to cattle (1:2? needs testing for exact ratio).
Horses being ridden by foot soldiers will not be counted towards the herd.
Disorganized Army debuff:
Temporary debuff after any battle fought, big penalty to your speed for a brief amount of time(1-2 game hours)