"Mirrors"

Regarding guessing the location of treasures – in my opinion, it doesn't depend on the roads; you either guess correctly or you don't. Even with average roads, this treasure will still be found.

The probability of guessing correctly can be minimized with proper scouting, so you can then make an informed decision about whether to go for it. Although, it has happened that it was precisely the thorough scouting that led to failure.