What is there to see between Dublin and Cork (but not *in* Dublin or Cork)?

I asked this on Quora, and no one answered, so I went ahead and answered my own question after having ridden between the two towns. There’s:

1. the ruin of Kells Priory  (“one of the largest and most impressive medieval monuments in Ireland”);
2. the Rock of Cashel if you take the northerly route, or some nice seaside towns (Dungarvan, Youghal) if you go by the coast;
3. The Irish Steam Preservation Society museum with lots of old steam-powered cars and tractors and such.