go figure - two days ago, my wife gets a request from my son to ride his bike. She went out with him and he rode all over, although, with training wheels. We thought it was a one-off request, but he came home from school yesturday and was gung-ho to jump on his bike and do it again.
She said he did really well and even got going on his own without the typical push starts he wants, except once up a hill.
Hopefully it continues and we see him progress before winter sets in!