I tend to get better results with Automobile mode but with "Avoid Highways" option set and then occasionally dragging the route or inserting a waypoint- than I do with Bicycle mode. Are you getting those dirt roads in bicycle mode or automobile mode, since I don't really get many dirt roads.
Good question. Your suspicion is right in that I usually use bicycle mode. I'll try car mode and "avoid highways" for comparison. Thanks for the tip!
On different topic:
I used to use RidewithGPS, but ever since learning how to get a GPX file from Google Maps, using GPS Visualizer, I've found that to be more convenient.