I like Kelty backpacks, as well. Never owned one of their child carriers, though. One thing I'd like to toss into the mix is that you start having your son walk along as much as he is able. If he's like my son, that'll be any day now, but for short distances.
Once he hits about two years, though, aim for "hiking his age." Nathan surprised us at age two when we visited Crater Lake and walked from the rim down to the boat dock for the boat tour. It's about a mile and 700 vertical feet. I figured he'd make it down just fine under his own power but I'd have to piggy-back him back up. Wrong, GORP-breath! He was slow but steady and made it all the way back to the car on his own.
By the time he was about 5-1/2, he made the 8 mile trip from Agnew Meadows up to Ediza Lake (400' down, 1500' up) with his own little backpack. Took all day, and he slept VERY well that night but he got a lot of surprised looks and congratulations from other backpackers we ran into along the trail, especially on our way back a few days later when they found out how far he had gone.
It takes some patience but with encouragement, hydration and snacks, kids will learn very quickly to enjoy even challenging hikes. It pays to start early, though...as a Scout leader, I run into lots of kids who, at 11, couldn't keep up with what Nathan could do at half their age.
Nathan was 12-1/2 when we did Whitney as a 3-day backpacking trip, Portal - Trail Camp, summit, Trail Camp - Portal.
The only trouble is, about the time they grow up enough to be useful pack horses, they go off to college and who wants to be stuck with Dad at that point? (No complaints...we did a second trek at Philmont this summer, 100 miles worth, and it was a great cap to our backpacking experiences together before he headed up to Northwestern this fall. Who knows? Maybe he'll even come along to
Mt. Ritter one more time now that he's horse enough for the climb as well as the hike to base camp at Ediza Lake. I've told him I'll lead him up the "easy" route whenever he wants to go.)
