From Seoul there are now fast KTX trains to Dongdaegu, and transferring from that station to the Seobu bus station can be easily effected by taking the metro to Seondangmot.
On the bus ride to Gayasan National Park I met up with a number of fellow travellers, both foreign and local. None of these prepared me for the climb up to the site. But the effort was worth it to say the least. To see such an important facet of Korean history up close was indeed a privilege.