I was going to go to Pwlhelli as part of my ALR in June.
Then I discovered a few things. If you leave 2 stops early, at Minffordd, you can get on to the Ffestiniog railway. So, you can take the miniature steam to Blaenau Ffestiniog, then come back via Llandudno Junction and the North Wales coast.
Alternatively, walk 1.5 miles from Minffordd station to the coast, and you arrive at the incredible village of Portmeirion, where cult tv series The Prisoner was filmed!