The backpacks are really great. I know some people that got one just to give their dog a job to do when they're walking. That often does help settle them down some. The one Murphy's wearing is the Approach 2 pack from Ruff-Wear. We've tried their packs and harnesses and everything they do has held up well and performed as advertised for us. Molly is wearing their Web Master harness. The nice thing about these is that they are very secure with two straps and snaps and they have a handle for helping your dog up and down over broken terrain. They're designed to be useful in SAR work, so they do a great job for serious outdoor hikes.
Murphy's got a lot of talents, but skydiving ain't one of them. Since we hike year-round and we usually take all 3 of them, we like for them to hump their own kit. We make up MREs for them, carry a hiking FAK, and also have them tote other stuff that they might need. We carry the water, our snacks, and the other stuff that we'll need. Murphy usually starts out with the pack, but if we're going to be out all day, I'll switch it to Molly after a couple of hours, then back to Murph. That way, nobody gets really exhausted from carrying it.