Ride Planner exports locations and waypoints into the GPX file. It does not export the highlighted route. The exact routing between destinations may be calculated differently within the radio than shown in Ride Planner. To plot a particular path, you may need to add waypoints along the desired route. Also, the route calculation can be affect by system settings such as route preferences (scenic, fastest, shortest or twisty) and avoidances (such as toll roads, unpaved roads and so on). See
Navigation → Route Preferences and Avoidances.