Treks are tricky for one proceeding in the nude (8)
I believe the answer is:
streaker
'one proceeding in the nude' is the definition.
(to streak is to run naked in a public venue)
'treks are tricky' is the wordplay.
'tricky' is an anagram indicator.
'treks'+'are'='treksare'
'treksare' anagrammed gives 'STREAKER'.
'for' is the link.
(Other definitions for streaker that I've seen before include "Naked runner" , "One running out of clothes?" , "he barely covers the distance" , "One making a dash without clothes" , "One barely running in public" .)