IdEaMaNi, how long it takes really varies among people. I was surprised Shri made it to Trail Camp in 4 hours. Trail camp is about 6 miles up the trail and is 4000' higher than Whitney Portal. Shri was only carrying 30 lbs, I think, which is quite a bit lighter than many who head up.
I would plan on 6 hours to haul a pack to Trail Camp, and if you get there sooner, that is good.
The switchbacks are completely snowed over at this time, so following those is going to take you longer, since you would be breaking trail (tromping through soft snow) for a lot more steps than if you go straight up the chute. Most people don't use the switchbacks until June after most of the snow has melted.
