What kind of incentives might there be to stay on the roads?
I have no idea about the surface area of feet and stuff. It makes sense that a creature with large feet and a low mass in tough soil might not leave tracks at all, but I haven't delved into it.
Overall, there has to be some reason to travel on roads. Right now they are meaningless.
Since some of the stuff about incentivizing adventurers to travel on roads appeared in the context of tracking, I sort of assumed that you won't leaving tracks if you travel along a road. This would have the advantage of preventing bandits from following your tracks straight to you, but on the other hand you could run into roadblocks if that is implemented.
I don't know about you guys, but I definitely don't move as quickly or as easily through a forest when picking through the trees compared to when I'm on a path. Now that we have the basic necessities of life (eating, drinking, and sleeping) in the game as well as a combat/movement speed split, it seems the main incentive to stay on the road would be that it's faster. This would save you daylight, food, water, and energy. This might be good if you want to travel for two days without stopping, whereas the same trip cutting through thick forest, tall grasses, swamps, etc. could potentially wear you out in half a day.
On the topic of road safety, will caravans always travel with a large enough number of guards to protect them, or will there be guards from the different civs patrolling the roads to keep them safer?
Also, now that goods are tracked from town to town, are caravan goods actually going to be tracked from their origin to their destination? For example, if a caravan carrying dwarven metalwork is ambushed on its way to a human town the mountainhome, will the bandit camp be filled with +steel short sword+ and ☼lead barrel☼? Would those same goods have showed up in human shops had the caravan arrived, or would they just be stored in the warehouses?