Google makes it easy to create a custom driving route map to any number of destinations but makes it almost impossible to transfer that route to a stand-alone GPS device. In this short video I show how to do it . Please Note; At 4:49 I show to send to device. That is incorrect. You need to click the 'activity' icon in the top menu and select 'direct'. Then click the route in the left menu and choose 'create track from selected route'. Then make sure the created track matches your selected track. Then send to device.
GPS Visualizer now requires a Google API key. A good alternative is https://mapstogpx.com/