Considering the account of Bilbo of his arrival at Rivendell in
The Hobbit, a distance of many miles from the Ford to the Last Homely House seems more than reasonable.
They crossed the Ford in the morning, and didn't arrive at the valley until dusk. And with Gandalf leading the way, too! Then again, maybe he was just toying with the Dwarves and knew the way all along.
I realize the particulars of Eriador geography weren't as clear-cut in Tolkien's mind when he wrote
TH, but still...