Here’s a great site about what to pack. Stolen unabashedly with LINKs to the original:
ALC allows one bag for each participant, weighing no more than 70lbs. Please think of the roadies who have to lift your bag in and out of the truck twice a day, and try to keep it well below that! 50lbs is the weight limit for airlines…
Ideally, everything you need should be in your one bag, including camping items such as your sleeping pad or air mattress, and sleeping bag. The one exception to the “one bag” rule is that you can have your sleeping bag and pad as one separate item, if necessary. Make sure they are in a bag, and clearly labelled with your name and rider number.
DO NOT USE BUNGEE CORDS! Attach them to your bag with webbing-type straps instead, or another secure strap that can’t snap and injure the roadies.
A well packed bag
This bag is approx 7200 cubic inches, 36 inches long with two separate main compartments and two side pockets. You can find it as a “split drop-bottom rolling duffle” bag online at campmor.com or sierratradingpost.com at a significant discount. Similar bags are also available at Target, Walmart, and sporting goods/discount travel/outlet stores.