OldShooter
Give me a museum and I'll fill it. (Picasso) Give me a forum ...
Actually, there is quite a good solution to that problem and it does not require having a separate GPS. We use this app: https://copilotgps.com/. All the maps are downloaded and resident on your phone or tablet, so you don't need any cell coverage at all in order to navigate. The US and Canada maps easily fit in my phone's and my tablet's memory. They also sell inexpensive maps for many other places around the world; we used their Norway map a couple of years ago with complete success.... We usually use Google Maps on our phones for travel and we are concerned that we will have spotty coverage whilst navigating. ...
There are still some things we like to have cell coverage for, like using Yelp to find nearby restaurants, but we have no navigation anxiety at all with the CoPilot GPS app.