I took the opportunity for a days driving in the mountains of Wales en-route to a business meeting in Bangor the following day. Here is the route and some great pics
I took the M4 to Jctn 25A and then on up to Abergavenny
From Abergavenny take the A40 and then A479 to Talgarth. This was great scenery and a good intro for what was to follow the rest of the day.
Continue on A479 but turn off onto B4567 to Builth - lovely country road.
Continue on A470 to Rhayader, stop in pub for lunch.
Take the B4518 loop round the reservoirs in the Elan Valley - 
There was some simply stunning scenery and beautiful roads and lakes. 
Cross Rhyader to B4518 to Llanidloes - a truly excellent road - press the pedal to the metal!
Continue on B4518 to Llanbrynmair - superb road
Drive over the hill and look down on Lake Clwedog 
Cross A470 to narrow road on and past Pandy to join A458
Turn right and then left to B4395 to Llamwyddn and Lake Vyrnwy
At the top of the lake take the mountain pass to Bala
This road is one of Gods own - no people and spectacular scenery.
However, don't do as I did and park up on damp slippery grass and need 2 cyclists to help you get out. Here are some pics of the area that I got stuck on. Beautiful spot, but ...... 
Continue on the pass to Bala 
Now how about this for one of the best snaking roads where you can put your foot down - and believe me ... I did!
Watch out for the sheep! 
From Bala take the A4212 to Lake Celywyn and then turn off onto B4391 to Festiniuog
Turn off this road onto B4407 - now THIS ROAD IS motoring heaven! Turn up the octane, tuen up the testorone, keep the pedal to the metal and just keep an eye for the sheep - I nearly had one for my dinner that night!
The B4407 joins the A5. Take this to Betwys Y Coed
Then on to the A4086 to the Llanberris pass - this road is jaw-droppingly beautiful
Take a rest in Llanberris in a local hostelry, view the lakeside and enjoy and savour your days drive as one of the best of your life 
(I then went on the short drive further to Bangor)
Hope you enjoyed the pics!!