@allen, there’s already talk about adding a Mapillary layer to OsmAnd, and maybe a routing engine that can take existing Mapillary sequences into account when creating a route:
Mapillary layer in OsmAnd (scroll down to @Sandra’s comment).
Project OSRM http://project-osrm.org/ uses OSM maps and has a similar drag-route capability to Google Maps, although ever since they dropped Imperial conversion from their routing demo system, I’ve found it a lot harder to use and fall back to Google Maps more often than I like (which is to say, most of the time now). Which sucks, because I’d rather use an OSM-based router to work on OSM-based stuff, and OSRM also has a nifty GPX export function that is lacking in Google Maps (yes, I know about other websites that will take a Google Maps route URL and convert it to a GPX file).