I use the Copilot RV app. I bought it years ago for $6.99 on sale. You can set the height of your RV to avoid low bridges and it will also allow you to avoid tunnels where propane is restricted. It is a stand alone system because the maps are downloaded to your phone so you don't need cell towers. When I use the tow car I just change the vehicle profile to car. Much better and cheaper than my previous Garmin's. You can put it on your IPad also if you want a bigger screen.