No coverage is one of the selling points when true boondocking.
Our families know if they can't reach us to just leave a message. We check the phones every few days.
People went camping for centuries before cell phones were invented. Somehow they all survived and western civilization did not crash.
Just don't rely on OnStar saving your family when you are boondocking!!
My friends elderly mother hit a deer in the foothills in California. Hit Onstar for help and NOTHING.
Daughter called to find out what happened. OnStar uses cell phone towers there were no Onstar towers in the area she had the accident.
Many think that OnStar is satellite based and always available. I know I did too. Well, no cell phone signal where you crash... no OnStar. :(