Sleeping gear
Packing your pack
Since you’ll probably unpack each night and repack each morning, you should put some thought into the process. Usually, it’s best to put your sleeping bag at the bottom of the pack in a truly waterproof bag. I don’t like to unduly compress my down bag, so I stuff it into a plastic garbage bag, and squeeze some air out. My bear canister, full of food, goes on top of this. Since it’s easily the heaviest item in the pack, I want it to ride high. That’s another reason not to overly compress your sleeping bag. Some clothing is stuffed around the side of the canister, and my cooking gear is on top of it. Over that, I put my jacket, and sometimes my lunch. My water bladder goes at the very top, toward the front. Snacks and other things that I’ll need during the day, mostly go in my pockets. This configuration works reasonably well for my top-loading pack. I have two external pockets on my pack—one for my tarp-tent and the other for an alcohol stove, fuel and a few other items.
Some packs have lots of features that look cool in the store, but just add weight and are not as handy as they seem. It’s useful to have some bungee cord to secure items to the outside of your pack. I carry my sleeping pad this way, as well as items that are wet and need to dry out. I also use a couple of safety pins to secure my damp socks and a washcloth. My hiking partner, Craig, thought I carried this to the extreme, and looked like a walking clothes-line!
Your sleeping bag, pad and ground-cloth are vital, but potentially heavy items. Summer weather in the Sierras is usually mild with night-time temps in the 40s or higher, so a 32 degree bag is usually adequate. Very good, lightweight bags can be had from Marmot, Feathered Friends and Western Mountaineering. Either down or synthetic bags are okay, but down is lighter. The key with down is keeping it dry! If your bag weight is much above 3.0 pounds, you might think about replacing it. Some thru-hikers use very light bags and wear extra clothing on colder nights.
Sleeping pads provide an insulating and cushioning layer between your bag and the ground. Inflatable Therm-a-Rest style bags are popular with hikers, but have two drawbacks: they’re heavier than closed-cell foam pads and they can be punctured. So if you carry one, you’ll also need a repair kit. Most thru-hikers use closed-cell foam pads, like the Z-Rest, and often shorten these as needed. Many thru-hikers also use their pack and extra clothing as additional insulation, putting these items on top of their ground-cloth and under their sleeping pad.
You will need a ground-cloth to protect against dampness. Tyvek is tough and light, and while not really waterproof, it’s close enough to work well. Nylon or sil-nylon is truly waterproof, but punctures more easily.
Packs:
Your pack has one main duty: to carry your gear comfortably. If you have a lot of heavy gear, you’ll need a heavy duty pack with a sophisticated suspension system. Of course, that sort of pack will weight more too, so it’s a vicious circle. Ultra-light backpackers make do with very light packs that have little or no “suspension.” They can do this because they’ve reduced their total pack-weight. The pack is usually the last piece of gear that you should buy. If you already have one that you like and it weights under five pounds, you’ll probably be fine on the JMT. You might want to consider a lighter pack, though, if you’re not really happy with your present one, or if it’s heavier than you’d like.
Gear makers provide a lot of variety, but consider your pack's actual function. You’ll be carrying it for at least eight hours a day, so comfort is important. Generally, the lighter your load, the more comfortably it will carry, but you’ll need a pack volume of between 3000-4000 cu in. If you’re carrying a bear canister, and you should be, your pack should easily accommodate it. Some super-light, suspensionless packs, like the Go-lite packs, work okay for very light loads, but if you use one, be sure to test it carefully. REI and some other retailers will let you return used gear, if it doesn’t work well.
New gear choices emerge every season, so it's hard to make specific recommendations that won't quickly get out-dated. Much of the new variety is probably driven by equipment makers trying to keep up with "hiker fashion," but there are some real improvements in design and materials as well. For specific recommendations on packs and other gear, check out online forums, like the The Backcountry forum, Backpacking Light, or Practical Backpacking. Successful thru-hikers generally prefer lighter, no-frills packs. Some even like stripped down external-frame packs, or homemade packs. There’s a nice list of lightweight packs with specs on the Litebackpacker site.
Cooking gear and Clothing