Any suggestions on how to link the Atholl Woods trail to the hermitage offroad?
Back down into Dunkeld, turn left after the bridge and pick up the riverside path. Under the A9, cross the wooden bridge, pass the Forestry Office and follow the road to the Hermitage main Entrance. Personally I would miss that bit out and just head back to Birnam and take the Birnam Glen Road (opposite the hotel gates). Follow the stream up to start the Glen Garr part of the loop.
You got a good day for it 🙂