It's only a couple of miles, but not too pleasant due to how close you are to the A9. Stop at Layby 79 (NN632756,
https://goo.gl/maps/r3bZibYu6YfpNSTK9), dump the bike somewhere down the track, towards the bridge under the railway, and start the walk from Balsporran. There is a larger car park 400m further N from Layby 79 with assorted trees, fences and posts to lock a bike to, but it may be hard to make it inconspicuous:
https://goo.gl/maps/cjoMYTpp8jLKLfto6