Minor route, I hesitate to say, is more expansive (7)
I believe the answer is:
broader
'more expansive' is the definition.
(I've seen this in another clue)
'minor route i hesitate to say' is the wordplay.
'minor route' becomes 'b road' (B-road).
'i hesitate to say' becomes 'er' (expression used when hesitating).
'broad'+'er'='BROADER'
'is' acts as a link.
(Other definitions for broader that I've seen before include "Larger in the beam" , "Wider" .)