Certainly something similar to what you want to do plotting a route is possible.
or
Use the MIT Map component as shown in the
National Park tutorial to plot multiple locations at run time and use the LineString to plot a trak.
App Inventor 2 developers use the FirebaseDB experimental control to store and download from Tags; these can be used to populate locations etc. on either a Google Static Map (which uses Google Map map tiles to display) or the Map component (which uses OpenStreetMap map tiles to display).
Is this what you wanted to know?
Regards,
Steve