I don't think the monster spawns ingame are at all indicative of what was intended lorewise. They respawn frequently to give everyone a chance to experience the danger, and present a challenge to roaming around in the dark in particular. It's a game mechanic.
Many monsters aren't even set up with the abilities they have in the books, as mentioned.
I think it's pretty clear that, for the most part, traveling at night would be avoided. Yes, there are dangers during the daytime, but I am sure plenty of caravans go all the way along the road without running into anything but a few packs of wolves and they most likely just flee.
On the other hand we obviously know that sometimes they stay out too late, because they got lost, were forced to take a detour, or a wheel fell off the wagon. A caravan with guards level 1-4 has great odds against packs of wolves and bandits, if they know how to fight together. But even one or two werewolves gets involved and a dozen guards can be slain in seconds with very poor chances of fleeing successfully.
