What characters know and what players don't know
The one reason I posted Turo knowledge post is –
I assume that there is information that your characters know, So I'm posting it as thoughts or knowledge, and the player can use them in IC interacts.
As for the reason Iuz's party is choosing the northern trail, and Atzil suggested the southern trail:
The northern "unknown" trail is much closer to the empire of Iuz, the southern trail is closer to where you came from. All the characters know this, it a simple geography.
You also know that it will take you extra weeks to make a detour to the region from the north ... and as Garl GLittergold told Turo - Time is against you
A common sense tells you that the southern passage through Veluna is much safer than the Northern passages.