The comments help to focus on purchasing the right equipment the first time versus purchasing items just to get by and then having to purchase or upgrade to wilderness equipment. Here are some URL links to camping and hiking specialty stores. This is the most critical piece of equipment since the Scout will be carrying 35-45 pounds on his back. The most important thing is that the frame, shoulder straps and hip strap must fit to the size of the Scout. Also the mesh on the back must fit.
Most backpacks have load-shifting straps on the shoulders and across the chest and waist.
These make it much easier to carry and distribute the weight. Internal or external frames are a matter of preference only. Buy a pack with as many pockets as possible and make sure that you review loading instructions with a knowledgeable store clerk. Also purchase extra straps for strapping the sleeping bag, tent, chair, etc. to the pack. A set of 8 will get you started.