Piro travels from Adrilankha to Southmoor at least twice, and both times appears to take the same route.
The first time, few details are given:
But the trip is described in much more detail the second time:
At the end of the first journey, they see Dzur Mountain to the north. I think that means the road they are on approaches from the south of Dzur mountain, and we're even told of a posting house in this general vicinity that might be a stopoff on this road:
I drew the road going from Adrilankha to this posting house, and noticed that the road seems to pass directly beneath Castle Black, which lines up with one of Vlad's observations:
At the end of the second journey, they are at a crossroads near the border of Southmoor, with Nacine to the east and Roughground to the west. I marked this spot where the road crossed into Southmoor.
As to which road is the Nacine Road and which is the Shallowway Pike, I think the strongest indicator is the names themselves: The Nacine Road presumably runs to or from Nacine, and the Shallowway Pike runs to or from the Shallow River and/or Shallow Sea.
There's no indication given exactly where Roughground is, other than at the other end of the Nacine Road, so I put Roughground to the west, about halfway between Nacine and Covered Springs.
Yalata
We are given the name of a couple of villages along the route from Dzur Mountain to Adrilankha. In both cases, I believe they followed the same path as Piro, along the previously mentioned roads.
Telnan made this trip in four days, with Yalata being the place he spent the night on the third, which puts it 3/4th of the way from Dzur Mountain to Adrilankha.
This puts Cambry 13/14th of the way from Dzur Mountain to Adrilankha.
Orlaan's Meadow
The next point I can locate is the spot where Orlaan found Aliera:
I think the point of the methodology of her search was that Aliera was pulled (in a straight line) from Dragaera City to Sethra in Dzur Mountain, and the fact that she found Aliera proves her methodology was correct, so I drew a line between the peak of Dzur Mountain and the former location of Dragaera City, and where that line crossed the Adrilankha River, I located the meadow.
That puts the meadow 336 miles north of Adrilankha, so a little more than "nearly three hundred miles."