Speed

Speed is measured in daily pace and depends on a plethora of things.

A party on the road can do 40km per day (8h)

Doing a forced march (12h) gives you 60km per day, you can't do activities and you make a DC10 Con save or get exhausted 

Going through terrain gives DisAdv on checks to detect you. It also lowers your speed to 25km.

Forced march here gives you 35km speed. The Con Sv is DC12 here.

Night march gives another 40/25km of movement and imposes another con save of DC15