google will allow you to download maps to the phone, so if you're say in the middle of a forest or something, and have no signal, you'll still be able to at least see where you are on a map. You won't be able to start new directions without service, but a drive you are already on will continue.
make sure you also download some of your Spotify or Apple Music playlists ahead of time too.
there will be a lot of areas of no signal
I typically use Waze when I drive (not often, live in NYC, so only when I'm on a trip) but I'll make sure I've got maps download to google if I'm going to be out in the boonies.