Iirc it was safe to jump from a moving cart. Moving onto...I don't know.
You can do shorter (1/10th) waits in adv mode, though yeah you'd have to premark the "train station". Still, crossing an entire pocket world and still being pureed is quite impressive.
As for speed, I can see other approaches, of course.
If a dwarf walks at 5 km/h, then ten times faster - 1 step instead of 10 steps a tile - would be 50 km/h. Relatively close to other gait options. Of course, this would mean a day lasts 2 minutes and 52,8 seconds and that a dwarf drinks every hour and sleeps and eats every two.
Alternatively, if 1200 steps is 24 hours and a tile is 2 m, then 1 tile/step is 2,4 km.../day. With this, a dwarf takes a hour to walk 10 meters. This one feels rather ridiculous.
On the other side, using raids a dwarf crosses approx ~8,75 world tiles in a day (on a brief look), which translates to slightly more respectable 13,44 km/day, using that same 2m figure. Or lot more, if you assume a town or even a village is bigger than just 2,36 square kilometers(tripling it to 40/day would boost it by around magnitude).
Still, even the first figure would mean the cart travels unstopped farther than a nuke's blast wave would burn it, which is rather forward-thinking in the 1400s.
@Jazz Cat: If you have any poultry, they will 'pick' (generate) slugs around them, so that's probably where.