Oldranger, Thanks for the trekking pole advice. My only problem is that I am currently on the East Coast and fly back home the night before our drive into Yosemite. If I fashion some homemade poles, I worry they won't make the trip.
As for the bag, I'm unfamiliar with the Yosemite high country. How warm is warm for that time of year (800-fill?). Would a 3-season bag do the trick? Is 2lbs too heavy? Aside from the Marmot bag, the Kelty Light Year MarkNM recommended looks good too. I'm a fetal position sleeper, does that effect anything? Winter backpacking and snowshoeing looks like something I would like to experience. So maybe I should be looking at a +15F bag? I'm 5'7 28yrs 150lbs, so if we go by the 20% rule, I should be carrying somewhere between 30-35lbs.