Stop Maps from refreshing and losing the route

I don’t get a cell signal in my parking spot at my home. So I try to look up directions when I’m leaving the house so they’re ready to go when I get in the car and pull out. But I’m always thwarted because the app will refresh and the location and directions I just pulled up disappear. I have to input the location and search for directions again either while I’m driving (dangerous!) or just after I’ve pulled out of my parking spot and have signal again, blocking the entrance/exit to the parking structure for anyone who needs to pass. It seems insane that they would design a navigation app that won’t let you pull up directions until seconds before you’re ready to start driving — am I missing something? Is there a way to get the map to temporarily save the location/directions until you’re ready for them.