Location one may have to set out for (4)
I believe the answer is:
site
'location' is the definition.
(site is a kind of location)
'one may have to set out for' is the wordplay.
I cannot really understand how this works, but
'one' could be 'i' (Roman numeral) and 'i' is found in the answer.
an anagram of 'set' is 'ste' which is within the left over letters.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for site that I've seen before include "Ties into building location" , "setting" , "Area set aside for building" , "Location or piece of land" , "Situation (of a building)" .)