John Kehoe and I hiked it in two days though I think it could be done in one. You start at Happy Isles, hike past Vernal falls and then Nevada falls. Somewhere past Nevada falls, there is a primitive camp with bear boxes where we left our backpacks.
I think it was the next day that we got up and went the rest of the way to half dome with daypacks, came down, broke camp and hiked back down to happy isles.
The portion to Vernal falls is hundreds of stone steps (though you could take an alternative horse trail which is dirt switchbacks). You hike past the falls and get sprinkled. Between Vernal falls and Nevada, it is more of a trail.
The last part of half dome is going up the cable ladders on the back of it. I don't remember that part being too bad. Once atop, it is the size of a football field and, of course, you have a great view of Yosemite valley.
One thing, of course, if that they don't let you go up if there are any clouds in the sky. The place is legendary for getting hit by lightning.
I remember when we got to the bottom of the trail, we were exausted and decided to eat at the restaurant instead of making dinner. (Of course, we weren't necessarily in the best shape). It was well worth the effort and remains a real high point in my memory.
