Run small vehicle for living in (7)
I believe the answer is:
scamper
'run' is the definition.
(scampering is a kind of running)
'small vehicle for living in' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'vehicle for living in' becomes 'camper' (I've seen this before).
's'+'camper'='SCAMPER'
(Other definitions for scamper that I've seen before include "Run quickly and lightly" , "Skip around" , "Run around" , "Run along quickly" , "Run about briskly" .)