This suggestion is more tongue-in-cheek but since we're letting our imaginations run wild I might as well throw it out there.

As mentioned, I'd be tempted to invest in a bus company for commercial and preservation purposes. With this in mind, I'd like buy a few old Leyland Nationals and introduce a new brand identity: 638 Buses!

The service would run via the old 638 route between Sunderland and Ryton Village (maybe even Crawcrook or Clara Vale) on a limited daily schedule with a PVR of just one or two. This would give enthusiasts and passengers the chance to experience a truly unique service with an old-school nostalgic feel.

Of course it would fail - but, if I have money to waste, why not?