Seriously guys, telling her to by a $300+ pack and an even more expensive new shelter just to save a pound is just mean! LOL
Also, not to be a negative nancy, but unfortunately I'm not sure the alcohol stove is going to be allowed, either this year anywhere, and in the NPs usually - apparently this is the new normal. While I am in to alcohol stoves I can commiserate with the Park Service. While the Starlite stove is immune to most accidents, the bottle of fuel is not. This is a case where the chance of idiots may trump flexibility, and the fire danger may be high in August. Be prepared and get an "official rulling" just before you go. Better to stick with the canisters, which will be lighter anyway on a trip of a week or more - though you don't get the BW bragging rights for it. Jetboil solTi w/removed canister tripod lid and everything but the stove and pot, with 16 oz ziplock bowl lid replacement 8.7 oz. Fuel efficiency - priceless. So yes, easy answer - Spend More! :-)
Depending on how you feel about it you might try just a tarp and a bivy like the zpacks one since mosquitoes will not be an issue. Going to sleep staring up at the trees and the stars is pretty nice. Less pack space used as well, which is going be an issue using a berikade in the arc blast.
The berikade weekender does in fact fit into the arcblast 52L, but there are some awkward spaces in the gaps. If you think it will help I can post some pictures of this. With the arc blast, more that with, say, the similar sized but more efficient shape for of the heavier Kalais, you will be dealing with volume issues. Still I think you can make it all fit.
Also, even for the squemish, there is probably less fundamental need for the filter in the sierra than almost anywhere else - just bring aquamira. That is all I have ever used in the sierras, decanted aquamira, small plastic bottles, you can premix in the morning. I bring a small piece of noseeum netting, and an extra gatoraid bottle cap where I have dremmeled out the top. Put the cap on over the mesh, and dip int lake or stream. Since you have a medical background you may have a higher standard, but this also save space as well as weight. Also less work.
Lately I have been using the Panasonic lumix fh6 (4.3 oz with battery included). Leica lens, and cheap. Zoom lens, but with an extra wide angle setting on the short end - equivalent to about 24 mm on a 35mm camera. This is nice for outdoor stuff.
Fits perfectly in a zimmerbuilt zipped pouch (http://www.zimmerbuilt.com/padded-shoulder-strap-pocket.html) with an extra battery or two, on my shoulder strap. Bring a flattened TP tube for sighting the LCD in the alpine glare, if necessary.
I am planning on doing the JMT in late August and September so maybe we will cross paths. I will be on a luxurious slow plan, with lots of fly fishing and peak bagging along the way. If I can just make it past labor day I will be able to stop grumbling about the crowds.