Yes -that is a trail a bike -she just turned 8 and is almost too big for it -but we were afraid she would get whiney.
It was supposed to be about 8-10 miles a day -with more mileage available for those who wanted it. But it wound up being less. The guides were good about judging the crowd and we had 7 kids in the group so we usually rode about 5 miles or so -then let whoever wanted to get in the van and go to camp and the others would ride on to camp on their bikes.
The youngest child there was 5.
I can't picture doing it with kids younger than that -but I am a bit uptight about kids- kind of type A if you know what I mean.
The first two nights were primative camping -no toilets- no running water.
I did not realize this when we booked -but I am kind of glad I didn't know. I might have refused and missed out. The scenery was amazing and we played in the river every day with no one there except our group.
We had campfires and made some mores and played frisbee.

The third night we stayed in a restored mill house that is now part of a state park. We had showers!!