The Cycle route alont the side of the A55 looks pretty good to me. I've not done it myself yet, much too far just now but looking at it for the future.
The cycle path runs over up the side of the hill and sort of bypasses the Penmaenbach tunnels by going over the top, it does indeed drop you down in the central res at precisly the worst possible place to attempt to cross. But Richard Brunstrom campaigned heavily and got two cracking big bridges in to allow the cycle lane to cross the carriageways. Ugly as you like, but seem to be exactly the right thing. I imagine the path over the top gives some pretty good veiws. The only dodgy bit of that path by my reckoning is that bit by Tal'y'bont (ish, its further towards aber than that really) where the cycle path is effectivley a 'pavement' to the A55. Looks terrifying to me. And always makes me double take as a driver when I see someone cycling on it as if they are coming From Bangor towards Llandudno it looks like some one is going the wrong way up the carriage way.