Bree to Weathertop
In Bree (At the Sign of ‘The Prancing Pony’; Bk 1) Aragorn tells Sam that Weathertop is halfway to Rivendell. I am sure that this was a slip of the tongue and that he meant halfway to The Last Bridge. Everything falls into place on this assumption, since the travellers took 7 days between Bree and Weathertop (involving a detour to the north) and 7 days from Weathertop to the Bridge (with Frodo in a wounded condition and unable to hurry) while there was a further stretch of 7 days from the Bridge to Rivendell. Aragorn was well aware of the distance, as he said later (A Knife in the Dark; Bk 1) when they reached Weathertop, that it would then take them 14 days to the Ford of Bruinen although it normally took him only 12.