I was looking at the Transpennine Express (TPE) website this morning and noticed two new rail rover tickets that may be useful to forum members, valid only on TPE, not other operators, but their services are frequent.
Both can be purchased up to a year ahead (very unusual), and both get the 34% railcard discount.
So you can stay in Leeds or Manchester say, and just day trip.
North of England Rover 4 days in 8- unlimited travel Hull-Leeds- Manchester- Manchester Airport- Liverpool- £79;
North of England City Experience 4 days in 8- unlimited travel as above + Newcastle- £99.
All trains are walk up, no reservations needed. It takes the stress out of making advance reservations on specified trains (which may or may not be cheaper), and you can just change your plans at will. You can also use all intermediate stations like Huddersfield (or maybe Thirsk for James Herriott, as examples).
The only restriction is a Monday to Friday not before 9.30am.