I've been able to figure out other nuances and gotten things like true turn by turn to work.
I had a waypoint for home so walking out of work the other day I chose the Navigate app and then picked my home waypoint. It was done on the fly rather than building something in GC or Basecamp. I had activity set to automobile and courses set to follow course in the navigation settings. It gave warning and countdown at each turn along with a splash page with information about the turn. I had tried something similar the day after getting the watch and I unknowingly had the activity set to pedestrian and I don't believe I had the 24k maps on it yet and it did navigate me along the road while driving and did give beeps at the turn along with showing arrows on the map but it certainly wasn't as full featured as my second attempt. Unfortunately I don't know if the activity setting or the 24k maps made the difference.