Hey, thanks for the report; so at each of those sites is a subtle hint in the form of a sign saying something along the lines of "crane overhead" to help suggest it;
Beyond that, I'll have a think on another solution to help (as Act 3 does have a route around the map to avoid using the crane)
I'll also make a note to find some time to add more geometry to denote the paths to some of the sites. Which ones in particular did you get stuck trying to find? Was it the massive radar dish one? (And you mentioned Act 2 had a hard-to-find site too?)
And thanks for the kind words! If you have a moment, please leave a review on the game page 😇