From North Manchester I always come M61, J6 way, through Aspull. Just google mapped the other suggestions:
M61 J6: 21.9 miles, 40 mins.
M62/M6: 29.3 miles, 40 mins.
M62/East Lancs/M6: 25.4 miles, 43 mins.
Hardly worth worrying about!
Regardless, somehow I always seem to set off 30 mins before kick-off and still make it.