Route planner

[andrew_s]

cycle.travel is good.

What I do use Google for is to quickly check routes generated if it looks like a section might be off road / unpaved. Google Streetview gives you a fighting chance of rerouting away from unsuitable sections before your ride.

In cycle.travel, if you click on the route, you get a popup that offers Streetview for the click point.
Unsurfaced sections are shown in green rather than blue, and there's also a "Find photos" option that will show nearby photos from geograph.org, which is handy to see what the surface is like for the longer off-road sections (UK only).