I think doubling up to AVP would be a reasonable, 'shovel ready' (!) start and building a second platform there too. I'd like other stations such as Claydon and Quainton Road too. With reasonable free car parking, they might act as rural railheads.
Extending the London via/Prince Risborough trains to terminate at AVP soon too would be the foundations of that link.
Extending the London via/Prince Risborough trains to terminate at AVP soon too would be the foundations of that link.