Check out
this picture from Precipice Lake at sunset. You should plan on spending a night there. I only stopped mid-day, but should have spent an overnight.
And be sure to get a picture of the
Valhalla/Angel Wings looking back toward Hamilton Lakes. I somehow missed the opportunity on my trip.
Don't carry more than one L of water, less most places. 3 Liters to start from Guitar, drink one on the climb to the JMT/MMWT junction, one more on the way to the summit (a little for the return), the third: drink or dump it soon after Trail Crest. There will be plenty at switchback 22 and at Trail Camp.
Insulation: Down is lighter. Just keep it dry.
Food: I try to take 2 lbs per day.
Q7: Consider spending the night on the summit! If weather is good, you will never regret it. There are many spots to use, and the summit hut is warm and quiet if a breeze kicks up. Eat a big mid-day meal by G.L.. leave Guitar Lake with 4 liters at 3 PM, and have a light dinner on the summit. You will only need a liter of water for breakfast and the hike down. I double-bag zip locs for hauling all that water to the summit -- no sense packing big containers all the way across.
