They do during summer. If you zoom into the Bear Camp Road, you can see that it currently says "(Closed Nov-Jun)". If you set your leaving time to July, you can see that the other route uses that road.
Excellent. That's the first time I've seen that feature.
There's still some odd behavior around bicycle routes. For instance, Google does not seem to show bike routes down CA-1 in middle California. I'm not sure what's going on there--hundreds of people do that route every year.