Thinking more specifically about the MML, might it be a good idea to do the MML only as part of other fill-in programmes? So many trains use the MML for part of their route that wiring doesn't actually change to electric traction a great proportion of the changes on it.
So, I'd do the MML:
Bedford-Sheffield, Kettering-Leicester via Corby, East Midlands Parkway-Nottingham, Nottingham-Clay Cross Junction, East Midlands Parkway-Clay Cross Junction via Derby, Ambergate-Matlock
As Well as:
Leicester-Birmingham New Street, Oakham-Stowmarket via Ely, Grantham-Nottingham, Ely-Norwich, Dore & Totley Junction-Hazel Grove, Sheffield-Moorthorpe Junction, Sheffield-Hull via Goole, Sheffield-Leeds via Barnsley, Sheffield-Retford, Worksop-Nottingham, Methley Junction-Goole, Pontefract Monkhill-Huddersfield, Leeds-Gilberdyke, Barnt Green-Bristol Parkway, Gloucester-Newport,
This would deal with all of the long-distance services passing over the MML, wholely electrify XC between Bristol/Cardiff & Scotland, XC from East Anglia to the West Midlands & EMT from East Anglia to the North West.