The place you seek is actually better transliterated as "Geumgang-Gul".
Geumganggul Cave is a cave located in Seoraksan National Park, in Sokcho, South Korea... It was once a place of worship and contains a Buddha stone. - Wikipedia
It's located very far northeast of the country. .
You can walk there from a famous temple called the Sinheungsa ...
Your speculations in the question about what the contrast might mean are on point. Specifically, the poem moves from grandiose claims to mundane reality. The claims are about the past (recall) or the future (next thousand years); the reality is the present (am waiting). That the day is windy underlines the contrast between reality (cold wind) and the claims (...
Thinking about this poem and the emphasis on the dogs being in the 'very middle' of the path, I picture the coupled dogs not like this
or even like this
but like this
In this situation the dogs can't separate until everything 'subsides' and can get hurt if they try to pull apart:
(this is a more detailed explanation from LovetoKnow.com, spoilered just in ...