As long as its open, it is a pretty tame trail, given the stats of your rig in your signature. It does not require a locker.
I've been over a couple times, but always took a whole day (hiked, picnicked, enjoyed the stunning scenery), so I cannot comment on the minimum time to get over it.
Keep in mind that it can always change every year after the snow/runoff, so what it was last year is not guaranteed to be what it is this year. I add that as a disclaimer, as I haven't been there this year.
It is a great drive though, and I highly recommend it!
Baby Beast 2- 1999 4Runner SR5
Baby Beast -1987 4Runner SR5-Gone, but not forgotten