This route was taken from Adrian Hendroff's wonderful book "The Dingle Peninsula", which I highly recommend for many more great walks around the peninsula with nice nuggets of local information and history.
I started tracking after passing the grotto, which is easy to find. The route takes the well known path up and then continues south, taking in the key summits on the way. Luckily a friend was around so we used two cars and saved ourselves hours of road walking. If you have plenty of time, set off early from the Mount Brandon Hostel, the road walk has stunning views most of the way as well.
After An Gearrán, we went away from the main pilgrim route and trudged through some slightly boggy land to find a quick way onto the track leading to lough geal.