The info is here with a guide how to do it: http://veloviewer.com/mapFlipper
So with strava route planner, road ride planning is great as it uses popularity of routes etc, not just standard google routing. You can show a heatmap of popular routes, as well as showing segments if you like that sort of thing.
I think this is a lot more useable that the terrible OSGetALife planner, or bikehike, which invariably has overshot it's API limits with OS.

