There are a number of "slate walks" in the Nantlle area. One of them passes the end of the track to Cae Mawr. Details of the walk, including a sketch map, can be found in the attached PDF.

May 2008:
The last time we did this walk, as we were crossing the corner of a farmer's field the farmer came walking across to us. At first we thought he was going to complain about us trespassing, but in fact he just wanted to show us a calf that had been born a few minutes earlier. It was just starting to try and get up: