The £65.60 is a period return allowing return at any time within a month. And, as well as being valid via Crewe & Shrewsbury, it also (for example) valid via Stafford-Wolverhampton-Worcester. For that latter route, it would be possible with split tickets to get the price down to about £36. But the last train back via that route seems to be about 4pm and some of the splits seems to involve having to stop at stations not called at by the faster trains.
For your chosen route and chosen trains, the best split that I can see is:
Longton-Shrewsbury £17.60 Anytime Day Return
Shrewsbury-Cwmbran £29.80 Offpeak Day Return
i.e. a total of £47.40
This would of course limit you to travelling via Shrewsbury, but the Shrewsbury-Longton ticket is valid via Crewe or via Wolverhampton.
[NB You could save a further 70p by splitting additionally at Church Stretton: Shrewsbury-Church Stretton £6.60 Anytime Day Return + Church Stretton-Cwmbran £22.50 Offpeak Day Return]
[I got distracted halfway through typing my reply and got overtaken by DJ737]