Lucky lucky. The whole of the Tal y Fan complex is about a dozen miles away, just over the river, Maen y Bardd and the Druid's Circle are both in the first rank of sites to my mind if you've not visited them.
I've not been to many of the sites around Capel Garmon (except CG itself, which is very easy access). Hendre Waelod tomb is fairly close and access is easy across a couple of fields on a footpath.