Thanks for the good advice Tom and Daisy. ... Daisy, this advice of yours:
Actually, the old external frame packs, with the upper bar (extender bar) are the best at getting the load directly on your centerline. With these packs, we always carried weight high when on a trail and low on terrain that required more body movement and climbing.
That is correct. For most ordinary hiking, you want to put the heaviest things on top and as close as possible to the back of the pack (the back of the pack faces the back of the human), even sometimes overhanging the frame itself if it doesn't hit the back of your head. The sleeping bag straps to the bottom of the frame, below the main bag, behind the waist belt. I advise a heavier duty abrasion-resistant sack for the sleeping bag. Tie compression straps to the frame. If the carry bag has a nylon handle, run at least 1 strap under it, both if possible, because sometimes the entire carry bag can slip out sideways. Continue upwards with heavier and heavier items. Heavy climbing gear went on top and we pulled the drawstring taut. The foodbag went atop that, then the climbing rope above that and as close as possible to the back. Then we pulled the top flap over those and secured it.
It's highly doubtful you have any climbing gear. You should be able to get most things inside the main bag and pull the main flap over with not much sandwiched in between, though that's a good place to put a flannel shirt or wind parka for easy access. I never carried a bear can in an EF pack, but if possible, try to fit it sideways at the top of the bag and pull the drawstring. If it doesn't fit, you'll need to go vertical and experiment. I always use a food bag and do suspension unless a bear can is required. Crampons, ice axe, or in your case more likely fishing gear straps well to the outside of the pack with bungie cords, whose hooks anchor somewhere on the aluminum frame that won't rub your body. Reverse the weight top/bottom if on a sloped snowpack, but still keep weight toward the back, not the front, of the pack.
This thing is not going to circle your waist like an IF pack. The rear pad is going to press against the bottom of your spine, all the way across the top of the gluteus. Sorry to be a bit anatomical here, but people with substantial gluteus mass usually get good support here. For people lacking that mass, the thing can slide down and thus put too much weight on the shoulders. Those people may need to crank the waist belt tight. The connectors on the back of that pad (usually has laces) need to be drawn very tight. The hip belt anchors to the frame on each side. The pads need to come up and over the top of your hip points (medical name is greater trochanter). If you've never used an EF pack before, it's possible the hip points could get a little sore (or even bruise a little) until you get used to it and the skin toughens up. Sometimes, the anchor ends of the 2 piece belt need to be moved up or down on the frame if it has changeable anchor points. Keep adjusting the thing on the trail until you get it right. Also make sure to adjust top anchors of the shoulder straps until just right. You don't want them going over the top of your shoulders and back down. Instead, you want them anchored just above the top of the shoulders if possible. Ideally, you want 25% weight on shoulders and 75% on hips. You might want to carry 1 or 2 extra pins and clip rings in your repair kit in case a limb snags a clip and the pin comes out and gets lost. IMHO, better to carry that tiny bit of weight than to wish you had it-same with 1 extra shoelace.