Does anyone know how long, on average, it takes to hike from Whitney Portal to Trail Camp?

About 4 hours up and 3 hours down.

My goodness; this is the first time I've read that question. How would you come up with an average?

4 hours sounds about right. Some faster, some slower, but that would be about the average. As for the round trip, I would peg the middle of the pack hiker taking about 14 hours (8 up, 6 down).