A also live in Wolverhampton (Bilston) and have done a similar route to Rhyl a few years ago. Just a couple of suggestions really. Do you really want to go thru' the centre of Wrexham as its easily avoided. Also, it gets very hilly for a time after Wrexham until Llanrwst. My choice would be to head North on the B5429 and then pick up the seafront cycleroute from Rhyl which is tarmacced and very good quality.