More unusual way taken by park-keeper (8)
I believe the answer is:
stranger
'more unusual' is the definition.
(I've seen this before)
'way taken by park-keeper' is the wordplay.
'way' becomes 'st'.
'taken by' says to put letters next to each other.
'park-keeper' becomes 'ranger' (I've seen this before).
'st'+'ranger'='STRANGER'
(Other definitions for stranger that I've seen before include "'Weirder, odder (8)'" , "Newcomer, alien" , "Less familiar" , "Person one doesn't know" , "'Fact is ........ than fiction'" .)