But I know how long it would take me on my own feet, with fair weather and no ill fortune: twelve days from here to the Ford of Bruinen, where the Road crosses the Loudwater that runs out of Rivendell. We have at least a fortnight’s journey before us, for I do not think we shall be able to use the Road.
--- Aragorn on Weathertop, before they are attacked by the Black Riders (October 6th).
How can the presence of the Hobbits and avoiding the East Road only slow Aragorn by a couple of days? I would have thought he could easily do 50% more mileage a day than a Hobbit, maybe more. In fact they did indeed reach the Ford in 14 days (October 20th) despite Frodo being injured.