I agree with Wert - I too seem to recall indications in the last part of the Chain of Dogs that a lot of ground is covered without much detailed descriptions, and you're right that that only makes things less believable. Story-wise it made sense though, he'd had the big dramatic Khundryl Burned Tears moment and then he needed to get to Coltaine's death as agonizingly close to Aden as possible, but the book had to pick up speed as it neared the Convergence and boring traveling scenes didn't really fit in that.

That said, in his defense, even if you look at real world maps alongside descriptions of journeys, there's bound to be some seeming discrepancies due to map projection issues, slight inaccuracies of the map, different kinds of terrain speeding up or slowing down a journey, and so on. I don't think there's much point to trying to calculate it too exactly.