Another C2C idea?

[Ajax Bay]

C2C in that it's UK most easterly point (Lowestoft) to most westerly point (St David's Head). ie widest way across.

Ahem. UK's westernmost mainland is Ardnamurchan, from which there is an excellent diagonale. My (planned) route:
https://ridewithgps.com/routes/49476532
Which I can get to ~1000km by (less fun) not using ferries.
But the thrust of this thread is an English C2C (so St David's is 'out' as is Ardnamurchan) but Land's End is 'in' scope.
There is an audax called the Trafalgar 1000 which I'd mine for route detail (SW London to Land's End) 500 there, 500 on way back sort of follows the route the officer bringing news of Nelson's victory took, having landed in Falmouth).

 

[Ajax Bay]

flying in with my bike (instead of hiring) and immediately boarding a train to Bristol (or a bus, if there are delays). Staying the night in Bristol

Give bus options a swerve with a big bike box.
Train via Reading (change) to Bristol is easy (2 hours; last train ETD after 10pm). Wait till 13 weeks before to buy tickets: 'Advance' ones go on sale then.

 

[mjr]

Give bus options a swerve with a big bike box.
Train via Reading (change) to Bristol is easy (2 hours; last train ETD after 10pm). Wait till 13 weeks before to buy tickets: 'Advance' ones go on sale then.

Not exactly 13 weeks. This page tracks the dates for each company/area:
https://www.nationalrail.co.uk/travel-information/advance-booking-dates/