Wow, so I read this entire set of posts with interest. I hike the Here is some infor that may help you:
Expect the temps to drop below freezing some nights you spend over 8,000 ft. It isn't unusual. I went with a down bag for this reason. I froze my tail off with bags rated over 30F. I prefer a 15F. I use them like a quilt and I love being able to pull the hood over the top of me.
Go with the Thermarest closed cell pads, they are cozy. They work great, you won't slip off of them on uneven ground and they are plenty warm. You will pay $30-45 depending on size. I camp where I drop and I don't eat where I sleep, except for a . Good for dealing with bears. You usually won't see them if you practice this. Also, put the shirt you use during the day with you bear canister. Practice eating leaning over the bowl and not over your clothes. It looks funny but keeps the food smell off of the body. Don't give them a reason to lick you :)
Stoves - The White Box stove in a tuna can stove works best in the Siera for me. I have made at least a dozen others and I like the versatility. You put the white box stove inside the tuna can stove for quick boiling or heating of water. The thing about the alcohol stoves no one seems to mention is you need to prime them and get the body of them warm. The combo of these two work so well that I got faster boil times. If you areally interested I could take some pictures and measurements of what I use and send it to you. Also you can make a pot cozy with metalized bubble pack and flume tape. I even have one for my bottle.
I use the BPE Nalgene bottles to cook my home made dehydrated meals in and my bag meals. then when I rinse the bottle out I drink it. You said calories were an issue. This helps you get every bit. Plus the measuring cup is right on the side of the bottle. Eat chocolate or your favorite candy bar at night, I call this supper, to get the added calories and fat you need in your diet. Don't forget the fat. I tried one of those low cal fat free trips and it was really horrible. Lots of things go wrong if you don't get the fat and calories you need. Especially at altitude. For a cheap home made goo you can find at stores along the trail I pick up Peanut Butter, Honey, gram crackers, coconut, marshmallows, and choclate or chips. That will cover the fat and calorie needs.
Also, freeze dried meats are a winner add to any meal. They will help with flavor and protein. Cheese is designed to last a while. That is why it exists. Expeirament with a few of these on the trail and it is also a good add for fat and calcium when you get sick of the junk food. There is lots of good flavor here.
OK, the pack. Everyone says use this and that. I have bought 6 different packs. All light weight (I have 4 kids, they are the best excuse for buying new gear). Here is what I have found in the Sierra. The Golite Pinnacle pack is the best size/weight/cost value. I have purchased all of these on clearance too. They are tough, 1 lb.10 oz. and you can use a pad to roll and hold it open (just like using the pad to hold the Army Duffel bag open, drop your shelter in the bottom, sleeping bag in the middle, bear canister on top of that, and whatever else you like to have access to on top. I actually am able to avoid stuff sacks for my bivy, sleeping bag, and tarp using this bag. It is really tough to. I used it's smaller cousin the Jam for 9 months continuosly with loads to 30 pounds (yes overloaded) and it is still in good yet used condition.
You are going to have an amazing time. I hope to live long enough and healthy enough to do what you are doing. I wish I would have gotten this bug when I got out of the Infantry.
Oh yeah, if you are man enough (haha) use Dr. Bronner's soap for doing dishes, washing yourself, cleaning wounds, and brushing your teeth - no not kidding, it isn't that bad. Otherwise just carry some baking soda for the teeth.
PM me if you need anything. I don't mind doing a resupply for you at some point if I am in town (I travel for work). Plus any excuse to get out. I have 4 kids who are just now asking to try backpacking again. So I have had several solos in the last few years. I would love to feed you some good dutch oven cooking on a trail day off if you are interested. By the time you get to Northern Cali you will be able to teach me something. The campsite and food will be my treat. Let me know if you are interested and I can work this with you as you go. Anywhere north of and including Sonora Pass (Stanislaus National Forest) would be best as I love these areas.