When replaying Point of No Return, it is absolutely vital to have a plan for dealing with this location (unless you're fine with accepting R2/no resolution) -- it is a mandatory gate for advancing Act 2. Although there are tons of clues available in the other locations, you cannot actually flip Vale of Pnath unless there are specifically no clues on IT, and hitting Shroud 4 without committing or playing cards can leave even dedicated clue-getters subject to the whims of a small number of tokens in the bag unless you can rely on multiple static boosts and/or triggered abilities. For many solo investigators it will be flat-out impossible unless specifically built-around.

(FWIW, in my personal games, I house-rule that Vale of Pnath's veiled ability can be triggered as if there were no clues remaining on it if the investigators have "surveyed the vale" -- with flipping Crag of the Ghouls or Peaks of Thok leading to remembering that the investigators have "surveyed the vale." I think that offers a more varied way for investigators to contribute to advancing the act.)