The village proper is on the other side of 206, across from the lake. There's the Atsion Mansion and store, which is now the ranger station. Behind the mansion there's a concrete ruin which was a Wharton era barn, and another ruined barn/storage building that I am going to assume post dates the barn.
A bit further down 206 is an abandoned cabin and down from that is the spot where the mill and furnace were.
Guy is right, there isn't a whole lot to see at Atsion compared to a place like Batsto or Allaire.