Hitch a ride with Tom (5)
I believe the answer is:
thumb
This clue is a double definition.
'hitch a ride' is the first definition.
(I've seen this in another clue)
'tom' is the second definition.
(folklore character Tom Thumb)
'with' is the link.
(Other definitions for thumb that I've seen before include "Tom's digit" , "Pollex, in humans" , "Hitch-hiker's tool" , "The hand's pollex" , "Tom ___ , traditional hero of English folklore" .)