A report in the National Monument Record (available via Coflein) gives a brief description of Caer Allt-Goch:
An enclosure set uopn [sic] & about the summit of an isolated hilltop knoll: the enclosure, 140m north-east to south-west by 40m, tapering to the south-west, is defined by a single bank on the north-east...
The author of the above is J Wiles, who also suggests that there is evidence of mining at Allt-Goch.