Travel times vary a lot according to conditions. How good is the road/trail, or does one even exist? How frequently are there stops to resupply? How much energy to do have to reserve to be on the look out for bandits or monsters (including watchmen at night), or to possibly fight them? Is there cargo? Do they know exactly where they are going and how to get there? What technological or magical aids are available to make travel easier? How extreme is the weather, and how predictable is it? If taking horses, how much grazing is there?

Well-equipped modern hikers have the better side of most of these variables. Modern light-weight, high tech equipment and high energy foods. Few concerns about bandits. Bridges over most if not all watercourses. And our trails are better than most mediaeval roads, which were usually plain dirt, with lots of foot traffic, which turned to thickly churned mud with rain.

Ascension's estimate is better as more of these variables are less ideal, but of course if you start staking the cards against your travelers, travel could become even slower.