cycle.travel (my site) aims to do that - the advantage of developing your own cartography! Minor roads in rural areas are shown earlier than in most other styles, but in urban areas they kick in later to avoid cluttering the map too much.
Just wanted to pop in and let you know I use your site all the time and it's still the best (and I've tried everything) at creating routes to avoid dangerous roads. Thank you for the awesome app.
One little feature that's great is the quick link to view Google Streetview images, and the only thing I'd change is to have it let me do that anywhere on the map (not just on the route) so that I can look at alternatives without dragging the route there first.
It's a good app, I was happy to subscribe once I used it a couple of times to find new routes about the city.
is that your site? I love it! I used it on an 800 mile bike ride 2 years go.
Wow, first bike router that chooses the same route I would to and from work. The others all take the steepest hill in the area instead of the slightly longer around the hill.