Just returned from a 'visit' to the Slovak part of the Primeval Beech Forests. Definitely hard to reach! The general trip report can be found here http://www.worldheritagesite.org/sites/beechforests.html
, but I would like to share some more practical details for future visitors of Eastern Slovakia.
1) It is really difficult to find out what is included. The large nomination dossier (downloadable from the Unesco website) has maps of each of the 10 designated areas, which you can compare with your own tourist or road map.
2) The core areas are remote and as far as I gathered not accessible by car. At Vihorlat for example, you only reach the core area if you are on top (or close) of Sninský kameň. The nearby lake (Morské Oko), which should be an hour's walk from the road, is in the bufferzone.
3) According to this regional website
, there is a walking path from Zemplínske Hámre to Sninský kameň. I did go to Zemplínske Hámre, and didn't find a trace (after succeeding in finding Zemplínske Hámre itself, which isn't on the Insight Slovakia map that I brought with me). It is probable that at least Morské Oko can be reached from the other side of the mountain, from the village of Remetské Hámre (there is a sign from the main road).
4) At first I thought that Nová Sedlica (the easternmost village in Slovakia and accessible by car) would be a better/easier option. It reportedly even has a little visitor center. But the core area here also is relatively a far walk (if walking there even is possible without a local guide).
5) 'Just' getting inside the Poloniny National Park isn't enough, only a thin stroke along the border with the Ukraine is part of the WHS.
So far what information I've gathered during my trip. I would love to here from others if they succeeded in reaching one of the core areas, and how!