I parked the car by the bridge over the Afon Tywi and set off crossing Dolauhirion Bridge and thereafter followed the described route.
The weather was just right for cycling being not too hot or cold and little wind.
The route shows two steep areas but the first which leads to Bwlch y Rhiw was not too bad and I cycled the whole way rewarded with a lovely descent passing Cwrt Y Cadno and then the entrance to Dolaucothi Gold Mine.
I was hoping the next steep bit on the outskirts of Caio would be similar to the earlier one, but no, this was beyond my output and I walked slowly up pushing the bike and munched a banana at the top.
My friend tells a story about Caio when he was asked by a traveller if he knew the way to CA 10, When the traveller showed my bemused friend a map he realised it was Caio!
I had a short lunch stop in Porthyrhyd ouside the old post office. This Porthyrhyd sometimes gets muddled up with the other Porthyrhyd near my home and about 7 miles east of Carmarthen..
From here it was relatively flat with one steep descent back to the car.