YP railcard is absolutely brilliant, really well worth it. Even if you're just an occasional traveller it should pay for itself within a few uses.

I normally get mine yearly (even though I realistically lose £20/year that I could save).

Try a google search for "Tickety Split" or "Split Train Tickets". There's a few handy tools/widgets that can show you cheaper fares by splitting your route. Just don't go ahead and book through them as they mostly use Thetrainline which charges a completely stupid booking fee; I advise to never go through them.
Write down the details it gives (for example instead of getting a ticket from Carlisle to Crewe, you'd get an outbound one for Carlisle - Preston and Preston - Crewe and the return maybe Crewe - Lancaster and Lancaster - Carlisle).
Then go through a TOC website (such as VTEC) and book those journeys stated.