Great biking road which takes you from Blairgowrie over Glenshee and into Royal Deeside. Braemar is a good stopping off point en route. For those who don't want to return via the same route (I think the return journey is even better), the B976/B974 road from Ballater to Fettercairn can be taken which will take you back to Blairgowrie via Kirriemuir.
Tried this route after the Blairgowrie - Ballater one posted by Rommel76751. Some pretty steep climbs and descents with stunning views at the top. Well worth a stop.