I am taking my son to Aberystwyth for a unit open day next Saturday, and want to carry my road bike with me to cover some kms while he attends different talks.

Any roadies out that way who might suggest an outstanding route of a couple of hours duration? Say between 50 and 70 kms?

Why not chuck the proper bike in and bob to Nant yr Arian?

Otherwise

https://www.strava.com/routes/4571080

The above suggestion is the best answer you’ll see! So much good mtb riding around there. You’ll miss all of it on the road bike.

https://www.strava.com/routes/4571080

I was going to recommend something like this route. I’ve never ridden that bit of A487 and not sure I’d want to (it might be fine though…). I’ve always gone straight through Tre-ddol and taken the back way to Tregaron, it’s a pretty steep bit of climb so keeps the mind focussed too.