Red route from Leeds? Arrive on outskirts (6)
I believe the answer is:
commie
'red' is the definition.
(I've seen this before)
'arrive on outskirts' is the wordplay.
'arrive' becomes 'come' (coming is a kind of arriving).
'on' means one lot of letters goes inside another (as in clothing \'on\' a person).
'outskirts' becomes 'mi' (I can't explain this - if you can you should believe this answer much more).
'come' going around 'mi' is 'COMMIE'.
'route from leeds?' is the link.
This may not be right. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for commie that I've seen before include "Eg, Marxist (colloq.)" , "Extreme left-winger" , "Red" , "Left wing" .)