ECML:
Cambridge (if electrified), Peterborough, Doncaster, Leeds, York, Darlington, Newcastle, Berwick, Edinburgh, Continue to Glasgow Central.
WCML, top&tail.
Watford, Milton Keynes, Coventry, Birmingham New Street, Crewe, Wilmslow, Stockport, Manchester Piccadilly, (Either: Wigan, Preston) (Or: Bolton, Preston) (Or: Bolton, Wigan, Preston), Lancaster, Carlisle, Caistars (Split) Glasgow and Edinbrugh.
Although like reverse square Johnson noise density (4KTRs) says, local passengers would mess it up, but just running silly late or overnights would be nice anyway.