Rhandirmwyn isn't close to any particular where (except Llandovery, but I don't think there are sessions there).

Tues: Aberystwyth (The coopers Arms), Llanarthne (Paxton Inn)
Wed: Aberystwyth (Ship & Castle)
Thurs: Brechfa (Fforest Arms - this is a Welsh session, Drefach Felindre (New Ship Inn)

I know there are other sessions in Drefach Felindre, in the John Y Gwas but I don't know what night - Monday I think, but the crowd seems to hang out there most nights.

In all cases, it's a good idea to phone first, just in case ...

sian