The fact that Mr. Dulates considers this a ride worth getting out of bed for may indicate the hilliness of the route...
I've done it; turned up late so chasing time for the first half. Very scenic. Except the bit between Prestatyn and Abergele, where you will get to observe the full effect of cycle paths in North Wales (banking that a velodrome would be proud of - with sand). It also has a bizarre piece of road where you will be riding up a hill in a housing estate, and suddenly you are in the moors. Peculiqueer.
Also, as Jethro says,, there is a downhill section. Make sure your bike has brakes.