Train from Dunkeld to Aviemore
Aviemore to Tomintoul via Ryovan Bothy and Abernethy Forest
Tomintoul to Linn of Dee via Glen Avon and Larig an Laoigh
Linn of Dee to Strathardle via Glen Tilt, Fealar lodge and Glen Fearnach
Kirkmicheal to Dunkeld via Glen Derby and Loch Ordie
Great route, easy done with two nights camping.
Almost a straight line right through the Cairngorms National park.
Good mix of single and double track.
Plenty good campsites and bothies en route.
<edit>probably not advisable in Feb though !!!! </edit>