I'd be extremely reluctant to go to any wilderness or hiking area and rely on my cell phone. Sure, coverage is much better than years ago, but even a few weeks ago I was driving a few hundred miles. I checked ahead of time to see about possible stops along the way, cell coverage, etc. because some of the route went through the middle of nowhere. Cell maps said I had full coverage the whole way, but there was a hundred mile stretch where every few minutes I'd lose coverage for a mile or two.