I've been able to lay a route out in Ride with GPS and then move it into my Garmin 305 as a course.

Last Saturday I was playing with the course feature and was able to get a map to come up that showed where I was and where my next turn was. Definitely not turn by turn directions but it would be something to follow on an unfamiliar route/course. There may be more features in the 305 than I've found yet, I'll just have to do some more experimenting with it.

Semper Fi