To the extent that I understand what you have in mind, I would probably do something like this:
There are essentially two initial choices: (1) Pursue bad guys in one direction or (2) go in some other direction for some reason.
If 1, then the meaningful decision points after that would be Pace (slow, normal, fast), Marching Order, and Activities While Traveling per PC: Keep Watch, Navigate, Track, Draw a Map, Forage, Work Together. The viability of those tasks are impacted by Pace - it's harder (or impossible) the faster you go. Each task provides a benefit if successful, one that is actually useful in context. Throw in random weather (temperature, wind, precipitation) to see if this throws a wrench in things. They have specific game effects that can impact the viability of travel tasks.
Now set a particular chance of random encounters on that path which is adjusted by the Pace. Perhaps on an 18+ every few hours. If Fast pace, you have a lower chance of encounters, but there is a trade-off of -5 to PP (Keep Watch) which means surprise is very possible if a random encounter is indicated (and the monster is being stealthy), plus other tasks are impossible (Forage, for example). You can then come up with a means by which you determine how quickly the enemy gets to destination. This could be a random roll or set number. If the PC's pace and success indicate they catch up to the enemy, then you drop into the Chase rules and resolve accordingly.
If 2, you would have the same decision points, but the Chase rules come out when the enemy catches up to the PCs.
In either choice, you can also set up planned encounters on top of the random encounters if you wanted to be sure there's at least some kind of "road encounter" along the way. Additional random encounters just increase the difficulty, especially if they end up having to short rest which risks letting the enemy get away or catch up to them.
This would be a pretty easy structure to implement and mirrors a basic framework that I use in most of my games. It's loaded with decisions to make for the players. I discuss it in more detail
here.