Dovahkiin can travel anywhere in Skyrim (although some time will pass). This is extra impressive when you consider just how big Skyrim is. For a low end of the distance, the distance from the volcano of Vvardenfall to the city of Almalexia is said to be 250 miles (or 402.336km).
For our mid and high ends, we'll have a look at the Arena manual, which says that Tamriel is roughly 2000km to 3000km from North to South.
191 pixels = 402.336km
1 pixel = 402.336km/191 = 2.1064712km
2.1064712km X 282 = 594.024878km
(Mid end)
676 pixels = 2000km
1 pixel = 2000km/676 = 2.95857988km
2.95857988km X 282 = 834.319526km
(High end)
676 pixels = 3000km
1 pixel = 3000km/676 = 4.43786982km
4.43786982kmX 282 = 1251.47929km
T = (60 X 60 X 21) + (60 X 35)
= 77700s
(Low end)
T = 594.024878km/77700s
= 7.64510782m/s (27.522388152km/h)
(Mid end)
T = 834.319526km/77700s
= 10.737703m/s (38.6557308km/h)
(High end)
T = 1251.47929km/77700s
= 16.1065546m/s (57.98359656km/h)
Final Results
Dovahkiin's travel speed (low end) = 7.645m/s
Dovahkiin's travel speed (mid end) = 10.738m/s
Dovahkiin's travel speed (high end) = 16.107m/s
Although this may not seem super impressive, keep in mind that Dovahkiin can keep this up for close to 24 hours. Also, this is assuming they travel in a straight line.