Try the AA, the RAC or multimap for LL55 2SG Caeathro.
Maps courtesy of the Sunday Times 'window on the UK 2000'
Glan Gwna is in North Wales at Caeathro, one mile south of Caernarfon on the A4085 Bedgellert road. Turn left into the park at Caeathro.
From Birmingham either go up the M6 turning left for Chester or take the A5 for Bangor.
From the South consider the scenic route up the A49, turning left after Craven Arms on the A489. Turn right at Church Stoke for Welshpool, take the A458 for Dollgelli, and the A470 for Porthmadog:-
Or for the adventurous turn right before Portmadog after a long down hill, for Tan-y-bwlch and Rhydd; go over the mountains for Beddgellert and Caernarfon.