Where to go miles and appear out of the fog (4)
I believe the answer is:
loom
'appear out of the fog' is the definition.
'where to go miles' is the wordplay.
'where to go' becomes 'loo'.
'miles' becomes 'm' (common abbreviation).
'loo'+'m'='LOOM'
'and' acts as a link.
(Other definitions for loom that I've seen before include "Of future event, seem ominously close" , "Weaving frame - seem ominously close" , "Bulk large" , "Impend, threaten" , "Menace - weaving device" .)