Start at the car park at the House of Bruar adjacent to the A9. Turn right up the old A9 to Calvine. After the defunct petrol station (check out those prices, I wish!) you will see a a green Scotways sign for the Minigaig Pass to Speyside. Head up this track. After the last house on your left before the A9, turn left and immediately right, passing through a little car park and you'll come to the short tunnel under the A9. This is a safer crossing than the one offered by turning right at the house. Now the climbing starts, steady and exposed. Fortunately, it's amongst a panorama formed by Ben Vrackie, Farragon, Schiehallion, the Drumochter hills and Beinn Dearg. It's also a good place to see black grouse and other upland and woodland-edge birds.
Soon you'll start the downhill (can be sketchy) to the former home of the laughing (read drunk) man of Cuilltemhuc (locked), found very pleased with himself in his bath, apparently. Head down towards the fords of the Bruar Water. These are generally low because of hydro extraction upstream. Many have been tempted to ride them and it can be done. Just look out for Pete Dogg's rock in the middle of the second (main) ford, it's a wheel stopper. Peter was (almost) uninjured but his expensive bike light needed intensive care! Anyway get across the fords as dry as you can and head up past Ruichlachrie (derelict with limited shelter) to the junction with the Banvie trails. Turn right and head down through the deer gate passing through woodland. Turn right at all junctions.
To attain the wonderful (and not a little risky) singletrack ending, turn right up the brutally steep but short path to the upper bridge over the Bruar Water. Head down the path along the top of the gorge (look out for walkers). If you feel the need to bail out then make sure it's to the right! Actually, it's great fun and you should stop frequently to appreciate the gorgeous (pun fully intended) scenery of the Bruar Falls. Too soon, you'll go under the railway and come out next to the retail phenomenon that is the House of Bruar.
It's not suitable for beginners or young children. The gorge is largely unfenced. There are many other routes in this area.
OS Landranger (1:50 000) 43 Braemar and Blair Atholl
All of this starts a stone's throw from the A9 at Bruar, about 50 minutes north of Perth.
Do the route clockwise.
It's fantastic in a low sun, it really causes the trees to glow red. Best done early morning, evening or at night with good lights.
Avoid Bank Holidays: House of Bruar measures its visitors in millions http://www.houseofbruar.com/ .
It's all rideable. At the steep wooden steps in the gorge, keep right and you can take the chute next to them, there's space for most handlebars, you may have to shoogle a bit!
Nearest and best bike shop is the rather fab Escape Route in Pitlochry 20 minutes away back down the A9; http://www.escape-route.co.uk/. This offers all facilities, services, banter and sympathy.
Great camping, food and beer in Blair Atholl less than ten minutes away.