In regards to High Speed Rail in Scotland and NW England, I would draw up plans for the following routes to be constructed, and to connect into a future UK wide HS network.
New Edinburgh & Glasgow Joint HS line, to broadly follow the alignment of the M8 (in between the Caledonian Railway and North British Railway routes, hence the "Joint" in the title of the line). This could be an enabling project for Glasgow Crossrail in conjunction with the main HS project. The Edinburgh end could be designed so as to leave the stub pointing tantalising in the direction of Newcastle for a future extension.
Construct a new Caledonian HS line from the New E&GJ HSR to Carlisle Citadel. This could approach Citadel station on the west side and have a new island platform constructed. This would provide a cross platform northbound interchange to and from the classic services, with the present day island Platforms 1 & 3 being used for interchange to and from classic southbound services.
Construct a new Preston, Lancaster, & Carlisle HS Railway, which would run on a much straighter and gentler graded alignment (with several tunnels). This would be an end on connection with the New Caledonian HSR at Carlisle Citadel. At Preston, the HS station could be sited near Salwick station, as it is close to the motorway, and would enable the service frequency to be improved at Salwick if the Parkway proposal that has been suggested previously is decided upon.
Construct a New North Union HS Railway line from Preston to the New Lancashire & Yorkshire HSR line (that would run from Liverpool to Kingston upon Hull via Manchester and Leeds), and onto the New Manchester & Birmingham HSR line, which in turn connects onto the New London & Birmingham HSR.
This would eventually provide a New High Speed Railway between London and Glasgow and Edinburgh via Birmingham and the North West of England. Perhaps when complete, maybe this route could be called the New London, North Western, and Caledonian Joint High Speed Railway?