With such a long motorway proposed, it's not surprising that the Company suggested that it should be constructed in four stages:
Stage 1 - Coventry to Salford
The first stage was selected simply because the Company thought that it would give the highest returns for the required outlay. Which, given that it would have served Coventry, Birmingham, Wolverhampton, Stoke-on-Trent and Manchester, which are 5 of the largest 13 cities in England, plus the large urban areas surrounding them such as the Black Country, the Potteries and the South East Lancashire conurbations, is perhaps not all that surprising.
The route would have started on the A45 to the west of Coventry, before initially heading southwestwards, and passing around the south side of Birmingham where the route would have been to the north of the present-day M42. It would then have turned north near Stourbridge, where the road would have passed between Stourbridge and Stourton before passing through what are now Wolverhampton's western suburbs. Continuing north, it would have passed west of Penkridge, Stafford and Stone (though generally a couple of miles west of the present M6) before being roughly on the line of the present M6 between Keele and Sandbach. North of Sandbach, the route diverged from the M6, passing to the east of Holmes Chapel and slightly to the west of Wilmslow before passing just to the east of Sale and terminating on the A57 in Salford.
There were planned to be 23 intermediate junctions.
Stage 2 - London to Coventry
The second stage (though confusingly sometimes referred to as "Section 1") would have started on the A40 at Uxbridge, in order to connect to Western Avenue for good access into central London. From there it would not have followed the modern M40, but instead a route further to the east - between Amersham and Chesham before passing close to the north and east of Aylesbury, west of Buckingham and very close to the eastern side of Brackley. It would then have headed to the east of Middleton Cheney, east of Southam before turning west between Warwick and Kenilworth and meeting Stage 1 between Kingswood and Dorridge.
Stage 3 - Altrincham to Liverpool
The connection to Liverpool would have left Stage 1 to the east of Altrincham, before passing to the north of the town and crossing the Mersey just south of Partington. It would then have passed through what is now the the eastern side of Birchwood before crossing the A49 just south of Newton-le-Willows and heading between St. Helens and Haydock before heading along roughly the line of the A580 and ending at Bootle.
Stage 4 - St. Helens to Oldham
This section was seemingly only ever vaguely planned, and has not yet been found in any great detail. It would have headed north-east from Golbourne, east of St. Helens, between Hindley and Leigh, and then between Westhoughton and Atherton before passing south of Bolton, north of Radcliffe and south of Bury, before curving south-east and terminating between Royton and Oldham, probably on what is now the A671.