Walk around Virginia - that's hard work! (7)
I believe the answer is:
'hard work' is the definition.
'walk around virginia' is the wordplay.
'walk' becomes 'trail' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'around' indicates putting letters inside.
'virginia' becomes 'va' (US state abbreviation).
'trail' enclosing 'va' is 'TRAVAIL'.
'that's' is the link.
Can you help me to learn more?
(Other definitions for travail that I've seen before include "In old use, the pains of childbirth", "Painful or laborious effort, like childbirth", "Hard work", "Labour, toil", "Toil - anguish".)