Camper Vans & Class Ber's only. How late is too late?

I felt really bad when I had car trouble, and then a 1-hour wait at the tunnel, and ended up pulling into yosemite at midnight. I was giving someone a ride, otherwise I would have boondocked outside the park. But we were as quiet as we could be and I just went right to sleep.

In general, I figure try to avoid after 9pm and be super quiet if you cannot avoid it.

Before 6pm is better of course, because that is the time when people tend to shift into quiet time. Of course, that would depend on the type of park :).