In reply to RockAngel:
More to add to the collection and keeping it local(ish) to Abergele:
Day around Llandudno/the orme: The copper mine on the Orme (as seen on coast) is pretty spooky, other orme atractions are the cable car, railway, nature reserve at the top, Parisellas Cave for (hard) bouldering, there is a new art gallery in Llandudno with a good cafe, Woodland Trust Reserves all round the area (Coed y Gopa - also has a bat roost in a grilled cave, Marle Hall Woods, um, some others Ive forgotten) which internationally important for the habitats present/more importantly are utterly gorgeous in spring. Oh, and dont forget sea fishing.
Conwy is lovely, the castle is great and the Albion pub serves good ale. Take a walk into the Carneddau from Sychnant Pass, behind Conwy - there are standing stones up there, visit the RSPB Conwy reserve (farmers market on Wednesdays), or go to the movies (llandudno junction, near tesco).
Moel fammau and the parts of Offas Dyke either side are underrated and little visited compared with other places, worth a tramp about (or mountain bike around, some good trails).
Theres masses more as you progress westward...If your son is a bit littler, pili palas on Anglesey is indoors, has butterflies, lizards, snakes; the new beacon climbing wall is fantastic for all abilities/ages, Greenwood Forest Centre is good, Plas y Brenin does family stuff that might be worth looking into and has gear you can hire if you are under equipped. Go carting at Pwllheli, surfing at Abersoch....Ill stop now