This was only my second visit to Wales, but Tremadog is amaaaaazing (and also wins top marks for roadside convenience and the chance to visit the holy shrine that is Eric Jones's cafe).

don't attempt it carrying a large bag, and expect to abseil down the descent gully.

Good information to have! I find that some guidebooks have a definition of "descent gully" which is ... interesting. And does not match my perception of what I can reasonably descend without a) a rope, or b) dying.