Ease with which yours truly gets entrance at back of US university (8)
I believe the answer is:
mitigate
'ease' is the definition.
(thesaurus)
'yours truly gets entrance at back of us university' is the wordplay.
'yours truly' becomes 'i'.
'gets' is a charade indicator (letters next to each other).
'entrance' becomes 'gate' (I've seen this before).
'at back of' means one lot of letters go next to another.
'us university' becomes 'mit' (I've seen this in other clues).
'i' next to 'gate' is 'igate'.
'igate' put after 'mit' is 'MITIGATE'.
'with which' is the link.
(Other definitions for mitigate that I've seen before include "Lessen the gravity of" , "Make less harsh" , "Temper" , "Extenuate" , "Mollify" .)