Hi Laura,
It sounds like you are well prepared. I have hiked Vivian Creek many times and I think it is the best SOCAL trail for preparing for the Whitney trail. I have also hiked the other trails you mentioned. One of my best hikes was from Icehouse Canyon to Cucamonga Peak to Lytle Creek to Alta Loma where I was living at the time.
July 13th a group of five of us went up the Whitney trail. This was my fourth attempt, two twenty years ago and one last year. The other four hikers: this was their first time hiking more than a couple hours. We left at 11:15P 7/12. A firefighter in the group dropped out before we got to two miles. The rest of us made it to Trail Camp by sunrise. The others, having not ever doing anything like this before wanted to turn back, which we did. I was a little disappointed I did not make it this year, but I have made it in the past, so I just thought I would go up next year alone.
I think a 11PM prior day start was a good thing, as you will completely miss the heat below Trail Camp. The trail is so clear a good head lamp is all that is needed.
If you want someone to hike with I would love to go, but if you leave at 2AM you will have plenty of company. Last year I was passing and being past by a group from Wisconson, they asked me to join their group. Which I did. It was great meeting new people.
Have fun, I am sure you will make your goals.
Remember wherever the mind goes the body will follow.
