Wander about in the mountains (5)
I believe the answer is:
range
I believe this clue is a double definition.
'wander about in' is the first definition.
(I've seen this before)
'the mountains' is the second definition.
(range of mountains)
(Other definitions for range that I've seen before include "Distance between weapon and target" , "Selection" , "Oven" , "Limits the area" , "Extent - cooker" .)