I've done it maybe 5 or 6 times, it is a classic and a great route. First 150km to Llandovery via Hay on Wye is fairly benign. The 150km loop from Llandovery through Tregaron and New Quay then back to Llandovery is tough but it's the 40km from Tregaron to New Quay which tends to destroy the legs (especially on fixed). Last 100km back to Chepstow has a couple of climbs but nothing too steep. You can usually grab a bit of sleep if needed at Llangattock about 50km from the finish.
Top tip - don't overdo the food at the Mariners chippy at New Quay, there's quite a climb that starts immediately as you leave the control
I've done it maybe 5 or 6 times, it is a classic and a great route. First 150km to Llandovery via Hay on Wye is fairly benign. The 150km loop from Llandovery through Tregaron and New Quay then back to Llandovery is tough but it's the 40km from Tregaron to New Quay which tends to destroy the legs (especially on fixed). Last 100km back to Chepstow has a couple of climbs but nothing too steep. You can usually grab a bit of sleep if needed at Llangattock about 50km from the finish.
Top tip - don't overdo the food at the Mariners chippy at New Quay, there's quite a climb that starts immediately as you leave the control