I would have closed Appleby to Carlisle via Langwathby and had trains take the NER route to Penrith and the WCML to Carlisle.
Penrith would generate traffic, Langwathby, Lazonby etc are just small villages. Heck, tourists from Yorkshire changing at Penrith may even have been able to keep the Keswick branch open - That was a post-Beeching closure. Also the NER route is fairly straight so higher speeds could be achieved, and trains could get up to their top speed on the WCML.
I don’t know where the Appleby bypass could have gone.