Try http://www.plotaroute.com/ -- it is based on google maps, but has a lot more functionality when it comes to plotting a route, and it allows you to save as gpx, kml, or even straight to certain Garmin devices.
Since we are in the topic - any website I can plot routes with and transfer to Copilot GPS app?
What I find handy now is to build the route for a day trip or to modify an existing route using the "browse the map" feature on the Zumo 660 (device).
I still use HD Ride Planner when building maps for bigger tours.
I am certain that this should be easily done on the smartphone app.