Pitch a tent for regular guest on university grounds (6)
I believe the answer is:
campus
'university grounds' is the definition.
(I've seen this in another clue)
'pitch a tent for regular guest' is the wordplay.
'pitch a tent' becomes 'camp' (I've seen this in another clue).
'for' says to put letters next to each other.
'regular' indicates alternate letters.
The alternate letters of 'guest' are 'us'.
'camp'+'us'='CAMPUS'
'on' acts as a link.
(Other definitions for campus that I've seen before include "University buildings and grounds" , "Grounds for a student" , "University estate" , "university position" , "buildings in Nottingham, say" .)