Railpage has available for download the new 2018 version of the All Australia Tracks Google Earth overlay. 

The 2018 version has some proposed lines in the Tenterfield Casino area as they are marked on the historical parish cadastrals obtainable from NSW Historical Land Records Viewer. Perhaps start at either Tenterfield Parish or Tabulam parish around a probably era and follow the marked surveys through the adjoining parish maps 

The new version can be downloaded https://www.railpage.com.au/downloads?mode=download.view&id=1095