They were almost 'within striking distance' of their goal. = Their goal was almost 'within striking distance'. [=they were close to achieving their goal]
He spotted the group 'at a distance of' one mile. [=he saw the group when they were one mile away from him]
('Brit') The book is better than the movie 'by some distance'. [=the book is much better than the movie]
(..) Our list of allies grows thin. By foul craft,Saruman has crossed Orcs with Goblin-men. He's breeding an army in the caverns of Isengard. An army that can move in sunlight and cover great distance at speed. Saruman is coming for the Ring. This evil cannot be concealed by the power of the Elves. (..)2001 The Lord of the Rings: The Fellowship of the Ring