the roadblock ruins turned out to be 'southern ruins' and it was an old meteor site
2 more fresh secrets as of today:
1st is not much of a secret - just before riverside a passage south goes to a locked demon cave, still have to open it :/ dunno how. The passage is a little overgrown, but clearly visible if you just stray off the road southwards.
2nd site isn't far off - just behind riverside, right after passing a bridge and a stone behind it there's an almost invisible path north leading to sungard ruins, only like a 0.5 cm gap between trees suggests its there, and its overgrown in vines to make it harder to spot too