Yeah, that’s the way I went. Tried to avoid the endless dual carriageway near Flint and ended up getting very told off for trespassing on a power plant or something similar. After that, the seaside cycle path was quite a relief.
I tried to come home the next day more inland, but the endless singletrack 15-20% up and down killed me so much that when I got a puncture near a train station and my pump broke, I was quite relieved.