Specific places where you might find signal. Only those useful for making a call or text are noted. Places not marked, you likely WON'T find signal. Strategy is to be within line sight of a town (unlikely), inside a National Park, or in direct line sight of specific peaks, namely the La Sals, Mount Pennell, or Humphrey's Peak in Arizona (for the Grand Canyon area). I still haven't identified the tower providing random signal in GSENM, though it could just be mountains to the south.