I go to secure parking after end of journey: I'm delighted! (6)
I believe the answer is:
yippee
'i'm delighted' is the definition.
(expression of excitement or delight)
'i go to secure parking after end of journey' is the wordplay.
'go' becomes 'pee' (both can mean to urinate).
'to secure' is an insertion indicator (inserted letters are secured inside).
'parking' becomes 'p' (abbreviation on road signs).
'after' means one lot of letters go next to another.
'end of' suggests the final letters.
The last letter of 'journey' is 'y'.
'pee' enclosing 'p' is 'ppee'.
'i'+'ppee'='ippee'
'ippee' after 'y' is 'YIPPEE'.
(Other definitions for yippee that I've seen before include "Excellent!" , "shout of excitement" , "Cry of wild delight" , "Exclamation of wild delight (colloq.)" , "An exclamation of excitement or enthusiasm" .)