The road is the A4069 between Brynamman and Llangadog,this time of year is great,no sheep,and midweek no traffic.Weekends,especially if the weather is good is full of picnickers ,walkers, and bikes.
If you are coming up from Devon on the M4 then you need to come off at junction 45,head for Pontardawe,into the centre,follow signs to Cwmgors, then Brynamman, and then Llangadog.If you head into Llandovery there are two very good biker cafes,The West End Cafe,and the Owls Nest.