The trouble with some/all of those so-called "unlimited" cellular data plans is .... their speed is thottled down.
You won't mind or notice the slower speeds while just texting, emailing, or general Net surfing, but try to get an unlimited plan at 4G speeds so that you can tether your phone onto a larger screen and stream Netflix or Amazon movies evenings all you want while you're camping. The sweet spot is unlimited data at high speed. Good luck finding that at a monthly price mortals can afford.