In my opinion the most important decision you will make is your pack. It needs to be of sufficient size to house your gear, while also fitting YOUR body. I highly recommend as your first step visiting local retailers. Try on lots of packs, have the store load it with about 25% of your body weight. Do NOT take money. Do NOT go prepared to buy. This is not a decision to be made spontaneously. It’s a bit like selecting your home mattress. Be methodical, take your time, make sure it’s as comfortable as possible, realizing of course that an elephant on one’s back can only be so comfortable.
Learn the lingo:
(1) FRAME: Most backpacks on the market today will have an internal frame. If you go to a yard sale, you might find an old-school external frame pack. Most daypacks are considered frameless. The frame helps transfer the load from your shoulders to your hips, where you want to support the bulk of the weight. You may also see the term, stay, which is independent of the frame, but helps with fit (it should be removed and shaped to your spine).
(2) FIT: Packs are sold as unisex or women’s specific, they can be sized small through x-large, they can be an adjustable size pack, and they can be sold by torso length (manufacturer’s provide unique guidelines). Hip/waist measurements also are important and some packs are sold with belts sized separate from the pack. You may also find the option of “L” style vs “S” style shoulder straps.
(3) CAPACITY VOLUME: Pack capacity is marketed as cubic inches or liters of packable space. Frequently you’ll find capacity recommendations based on length of trip. In my opinion, capacity is much more dependent on gear size than on trip length, with the added consideration of food and water requirements. While capacity may be the same in a pack with and without pockets, you’ll be able to store considerably more in a streamlined pack.
(4) CAPACITY WEIGHT: Some packs will have a maximum capacity weight for a comfortable carry, usually those designed for lightweight or ultralight packers. You need to consider your base weight plus your consumable weight. Remember water is HEAVY at about 2.2 pounds per liter.
(5) PACK WEIGHT: Pay attention to the actual weight of the pack empty; you’ll be surprised at the differences. Extra zippers, pockets, padding, straps and cording add unnecessary weight. Some fabrics weight considerably more than others. Remember the weight of your empty pack counts toward your base weight. My recommendation is a base weight of 15-20 pounds.
(6) ACCESSORIES: Do you need water bottle pockets? Do you need a hydration bladder compartment? Do you like waist belt pockets?
(7) RAIN COVER: I purchased a rain cover for my first pack and have since changed to lining my pack with a garbage disposal bag and carrying a cape to cover me and my pack if it rains. The lined pack also provides my gear with a level of protection should I fall in a creek or sit my pack on wet ground. Recognize that budgetary constraints and/or lack of a full commitment to long-term packing may lead you to making a decision less than idea. It’s okay!!! You can always sell and upgrade. This is truly part of the process.
My current pack of choice is a Gossamer Gear Mariposa Ultralight. It weighs 25 ounces, has a maximum recommended carry weight of 30-35 pounds, and capacity of 4,244 cubic inches or 69.5 liters. Torso length is used to determine sizing of pack; hip belt is sized separate. Initially the shoulder straps bothered me, but after the first or second outing they softened up and now are quite comfortable.