Im looking for non tactical. Ill mostly be packing a hammock or lightweight two person tent, food for three days, tarp, bag,and some extras. I like to store items in small cases or poches before packing into pack. I dont think I would need anything more than a 35 liter pack that I can lash bedmat or bag to.
Packweight/volume is a highly personal thing that depends heavily on packing philosophy and local conditions.
My kids a bit older than yours and I understand the issues having gotten to the other side of it. Here's what works for me....
I prefer to carry a pack in the 5000 ci (not liter, but cubic inch) range. I would rather have a light load cinched down in a larger pack than to try to over load, tamp, stuff and curse at a trying to fit too much in a small pack. I strongly prefer a more robust suspension and value the versatility of a larger pack. I entirely dismiss and disagree with the logic that a large pack leads to over packing. This is true only if a person doesn't have the time, interest or commitment to track what the carry and to make hard decisions to leave stuff behind, even if the pack has more room.
I mention this because I've found that having kids along means I end up carrying more.
I put both my kids into Kelty Redwings. They had a suspension that would cinch down to their small waists and I figured it was a decent pack they could use as they grew up into young adulthood as a travel pack. Despite my loathing of panel loaders, the packs have worked well for them.
For the first several years, all the kids carried was their clothing, toiletries, safety equipment (whistle!!) and snacks and water. I carried their sleeping bags and the community tent and cook gear. Translation, my dad pack was much heavier than my hike with my buds pack.
If I had to replace my pack today, I would test ride both the Mystery Ranch packs (the old Teraframe design, now NICE Frame) is a well proven classic and the Gregory packs like the Whitney or Palisade (both long time designs). My current pack (an old, modified TNF from the stone age) has a direct connection from the stays to the reinforced hip belt, a design characteristic of the Gregories. I really like this and am very, very used to it. I have no padding on my hips/butt and a good solid connection to the hip belt helps keep the weight on my hips well. For me and my body, I would start with Gregory but Dana->Mystery Ranch is a no-brainer too.
If you are committed to a smaller pack, another one not mentioned yet is the Jandd Sufa Lite. It's in the 3.5L to 4.0L range depending on size and a very tough pack. I don't think Jandd's suspension works above this size, but we've had and pounded on 3 Jandd packs and several Jandd bike accessories for years. Bullet proof stuff. But I wouldn't go above the Sufa Lite in their line.
