Bad place to cross river -- standard package travels this way (6,4)
I believe the answer is:
parcel post
'package travels this way' is the definition.
(postal system for packages)
'bad place to cross river standard' is the wordplay.
'bad' indicates anagramming the letters.
'to cross' is an insertion indicator.
'river' becomes 'r' (abbreviation for river).
'standard' becomes 'post' (flag carried on a post).
'place' anagrammed gives 'pacel'.
'pacel' placed around 'r' is 'parcel'.
'parcel'+'post'='PARCEL POST'
(Other definitions for parcel post that I've seen before include "Means of sending packages" , "How something's sent" , "Mail service" .)