Search found nothing on actual use.

I have a 305, but don't use and don't care about the HR or Cadence. I love it for the racing against a ghost rider, navigation on a course, and standard bike computer detailed info.

Because navigation around a course I've plotted (not how to get here to there) is one of my primary uses, the 605 looks ideal for me as it can display actual street maps. That way I could alter a course on the fly by trying out a new road and easily seeing where I can come back to my plotted course (of course it would need the detailed map SD card). I also know it can provide turn by turn directions but again I don't ride to get to specific places. But, how does the course work in the 605?

My 305 simply has a squiggly line of my imported course, and I follow that line by going down the road that keeps me on it. Except for some 5 or 6 road intersections where it can get confusing, it keeps me on my intended path but there are no turn indicators. So, does the 605 provide turn-by-turn for courses, or only for address to address entries.

For those who have it, please tell us all about the course navigation features. The Garmin website doesn't say much.