Backpacks
This is a resource to introduce many of the questions and hopefully will guide you through a few questions, here are some to keep in mind:
Usage. Such as Day hiking, Multi-day hiking, or Expedition. Scouts fall into Weekend or Multi-day hiking, which would use a 45-70 liter pack.
Frame type. Internal-frame, External-frame, and Frameless. Scouts should start with Internal-frame backpacks.
Fitting the pack. A pack should fit a Scouts torso. A section below describes how to do that. Backpacks should list a range of torso lengths they can adjust to. Some packs adjust more than others. For growing Scouts this may be an option to look for.
Other features:
Ventilation. Some packs have a suspended mesh panel which is a trampoline-like design where the frame-supported pack-bag rides a few inches away from your back. Others have ventilation channels or chimneys to vent heat and sweat away from the body.
Pack-access & Pockets. This is how the main compartments are designed and how many pockets are added to the pack. Some packs are top-loading, others use zippered compartments. Pockets can be on the hip-belt, the top-cover, sides, etc. Here there is always a trade-off between accessibility and weight (everything counts when hiking 10+ miles). Some pockets are good, for water bottles, first-aid kit, rain gear, etc. Mostly this becomes a personal choice.
Raincover. It will rain while you are out on the trail, eventually. See how to protect your supplies either with a dedicated rain cover for the pack and/or keeping your supplies in water tight (& lightweight) bags.
Hydration Reservoir. Most packs will have dedicated space for a water reservoir. If you want one, make sure that the pack includes it.
Resources:
https://www.ems.com/how-to-choose-a-backpack-expert-tips-for-finding-the-right-size-fit-and-features
https://www.backcountry.com/explore/how-to-choose-a-backpack
https://www.outdoorgearlab.com/topics/camping-and-hiking/best-backpacks-backpacking
https://hikerdirect.com/packs/internals.html // discounted equipment
https://www.geartrade.com/hiking-and-camping/backpacks?sort=new // Used equipment
Measuring your torso
To determine your torso size, reach behind your neck, bend your head forward, and find the C7 vertebra: It’s the bone that sticks out the most on your upper spine. Next, locate the iliac crest. It’s the top of the hip shelf on the sides of your hips. Finally, have somebody take a cloth measuring tape to take the distance from the C7 vertebra down to the point of your back that’s at the same level as your hips’ iliac crest. This distance is your torso length.
For the pack to fit correctly, the distance from the top of the shoulder strap to the hip belt needs to accommodate your torso length. Keep in mind that torso length is not the same as height. A tall person can have a short torso, while a smaller person can have a relatively long torso. All full-size backpacks should list a torso-length range in inches.
Be aware that some packs have an adjustable torso length, meaning the distance between the shoulder straps and the hip belt can be lengthened or shortened, while others have fixed lengths. Also note that some packs are sold in multiple sizes, so the torso length can vary from size to size. [from ems.com]
Resources:
Example #1. Granite Gear. Blaze 60
Torso: Short (15-18"), Regular (18-21"), Long (21-24")
Capacity: 60L
Hydration port & Internal hydration sleeve
Cost: $203
Example #2. Alps Mountaineering. Baja 60
Torso: 15.5" - 20"
Capacity: 60L
Hydration port & Internal hydration sleeve
Cost: $129