Watch out with the sleeping bag; some kids still have occasional accidents at night up to age 8 or 9; some even later. (Unfortunately this runs in my family.). You definitely don't want the kid in a down bag until there have been no accidents for at least the past year or two!

The North Face Tigger is an excellent sleeping bag for kids up to 58" tall. It's synthetic, warm, quite washable and not overly heavy. By the time they outgrow that, an adult down bag will work fine. If it appears the young man or women will be a tall size when (s)he is grown, get a tall adult size once the Tigger is outgrown. That's what I did!

If you look in the "Hiking with Kids" section of this forum, you'll see a lot of complaints (including my own) about the lack of lightweight backpacks for kids that have good supportive structure to them. The supportive structure is essential! IMHO, the Deuter Fox 30 is a truly comfortable and supportive backpack. It's also almost infinitely adjustable. If the manufacturer would just use a lighter fabric (such as Dyneema) and leave off all the gewgaws, it would be a pound lighter and just as supportive! However, the child may have other ideas. My grandson, when I got him the Fox 30 at age 9, took one look at it, fell in love with it and absolutely refused to let me "lighten" the pack (more aptly described as creative butchery) by cutting off some of the excess gewgaws. At least this way the pack will be fully salable even after his younger sister and still younger brother have outgrown it!

One great thing about the Deuter Fox 30 is that it contains more adjustment features than any pack I've ever seen, and the literature that comes with it gives considerable detail on just how to adjust the pack to the child. You should be able to find one for under $100. I just did a quick google shopping search and found it for $79 several places, including Next Adventure here in Portland, OR.

Swizzle, please do remember that young children have immature bones, muscles and joints and can't carry heavy weights. 10% to, at the very most, 15% of the child's weight is a more than sufficient load. I'd say no more than 10% if you're using a cheap kids' book pack (which won't support much weight) and 15% if you're using a supportive framed pack such as the Deuter Fox 30 or a similar pack. In the meantime Dad (or, in my case, Grandma) gets to carry part of the kid's load. It's most important that the kid have a good time and learn to love backpacking and the outdoors. That's not going to happen if the child has too heavy a load for his immature body (which can cause permanent injury) or an uncomfortable pack!