Path out of brush to cross river (5)
I believe the answer is:
trail
'path' is the definition.
(I know that trail is a type of path)
'brush to cross river' is the wordplay.
'brush' becomes 'tail' (brush can mean an animal's tail).
'to cross' indicates putting letters inside.
'river' becomes 'r' (abbreviation for river).
'tail' enclosing 'r' is 'TRAIL'.
'out of' is the link.
(Other definitions for trail that I've seen before include "Beaten path; be in losing position" , "Fall behind" , "Drop behind" , "Beaten path through the countryside" , "Beaten path; follow" .)