Challenging trip (4)
I believe the answer is:
trek
(Other definitions for trek that I've seen before include "Long difficult walk" , "Long hard journey on foot" , "Slog" , "A long hard march" , "Difficult journey on foot" .)
I believe the answer is:
trek
(Other definitions for trek that I've seen before include "Long difficult walk" , "Long hard journey on foot" , "Slog" , "A long hard march" , "Difficult journey on foot" .)