does net & cell work if driving in the middle of nowhere?

I just had to call Verizon and have some roaming minutes removed from Canada. We were parked in Algonac State Park in Michigan and it is on the river with Ontario across theriver. Since we have a couple of Granddaughters and a Great Grandson living there we get there often. (next week again) When we really get to Canada we turn off the cell and just use the Onstar in the car. That uses the Verizon network also but has no roaming charges, just exorbitant for everything.