In order to climb Mount Whitney you first need to obtain a permit from the Forest Service. With permit in hand, you can hike the beast that is Mount Whitney. My expierence with the permit lottery is I put in for a permit three years in a row, and pulled a permit two of those years. Your expierence may vary, depending on factors on how large your group is and what days you are willing to hike. I am assuming days like Labor Day weekend are more popular than a day mid-week.
I left the trailhead at 3:00AM, summited at around 10:30AM and was back to the car by 4:30PM. The trail is well marked, generally following Lone Pine Creek westward up a canyon. The trail wasn’t technical, although there are lots of spots where a fall would mean serious injuries or worse. This would be a tough hike if you have issues with a fear of heights. The very bottom part of the trail has some tree cover, but it disappears after Outpost Camp. The 99 switchbacks start just after Trail Camp, and it seemed like this was the hardest part of the trail. But really, the hardest part is the last 2 miles of the John Muir trail to the summit. The John Muir Trail is steep, rocky, exposed and above 13,000 feet. You can see the summit in sight the whole time, but those last 2 miles are a slog.
When I hiked this trail, most of the snow had melted. There was a small patch near the summit that the trail was carved into by lots of boots. There is plenty of water between the trail head and the start of the 99 switchbacks. I had capacity for 4.5 liters of water, and I refilled once on the way down between Trail and Outpost Camp. If I were to do it again, I would fill up before starting on the 99 switchbacks, just for piece of mind.