Coach tour arranged, crossing heart of Montana (5)
I believe the answer is:
tutor
'coach' is the definition.
('tutor' can be a synonym of 'coach')
'tour arranged crossing heart of montana' is the wordplay.
'arranged' is an anagram indicator.
'crossing' is an insertion indicator.
'heart of' means to look at the middle letters.
The middle letter of 'montana' is 't'.
'tour' is an anagram of 'tuor'.
'tuor' going around 't' is 'TUTOR'.
(Other definitions for tutor that I've seen before include "Private or university teacher" , "Coach, teacher" , "He shows us the way" , "Personal coach" , "Guardian" .)