Google Map Links

[asp]

the waypoint list is displayed first and I guess most users would expect the route view

Yes, showing the route is certainly good, but showing the waypoints is ok, too. Only a matter of the point of view...

the last position of the Google Maps URL sometimes was some invalid position

I have that, too - but not always. In my case it was a position from the beginning of the route.
Maybe you could detect if the last waypoint position is wrong by comparing it with the last coordinate of the route?