The route from Tomintoul to Strathdon is 17.7 miles in length and entirely in the Cairngorm National Park. It has climbing of 1,729 feet and has been given a difficulty rating of 9.This is a tough stage which takes in the Lecht, perhaps the hardest hill included in the RTN153. Whilst it is slightly easier from the Tomintoul side, It is not for the faint-hearted and you have to be physically prepared and properly dressed. The Lecht is high and exposed, the weather unpredictable and it can be very cold and windy. But it is also magnificent and some of the views are breathtaking, especially west towards the Cairngorm massif. This is Scotland at its best.Tomintoul, meaning Hillock of the Barn, sits at 1,132 feet above sea level. It is in Moray and the Cairngorms National Park, as well as being on the Malt Whisky Trail. It has a fine distillery which is worth a visit, and is home to the Whisky Castle, one of the best whisky shops in Scotland. Alongside tourism and whisky, the other major industry is farming. 
You head southeast out of Tomintoul and straight into the climb to the ski station on the Lecht. The ascent lasts 7 miles so it is longer and less steep that the reverse route, but there are still some severe ramps. You reach the high point of 2,116 feet at mile 7.5. Hopefully the day is fine and you get the chance to enjoy the amazing views. The descent is around 2 miles in length and is very steep (with some gradients of 20%) and technical so please take care. You pass Corgarff Castle at mile 9.3 – open to the public, this beautiful white clad, fortified building was built in 1530. The remainder of the route heads broadly east on the A939 and then the A944. You will quickly notice the change of scenery as you move away from the stark beauty of the Cairngorms and into a more classic Aberdeenshire landscape. From mile 9.9 you are gently heading downhill and will be doing so until the finish, though inevitably there are a few lumps on the way. You join the River Don at mile 11 and follow its meandering route downstream through woodland. You enter Strathdon from the southwest and finish in the centre.Strathdon is a village, but it is also an informal geographical area which takes in the village of Bellabeg. For many years the area was called Inverlochty due to its location at the confluence of the River Don and the Water of Lochty. There is a war memorial in the village, which hosts a traditional Highland Gathering. It is only a small place so you should carry some extra provisions.
By clicking on the play symbol on the graphic below you can see route map. The elevation profile of the ride can be seen via the Hills tab with files for use with a GPS device also available for download. If you take any photos of the route that youd like to share, please submit to neil@velodays.com
Route map for Tomintoul To Strathdon by Neil Innes on plotaroute.com