my kids are at their best in the morning around 10ish. we have good luck if we get them up - not too early - feed them something and get in the car or on the trail early before lunch - then bring a lunch.
I think timing is everything.. Also a consideration is their intestinal timing. My kids sometimes don't like to eat cuz then they have to "go". So if we can time the rides to be during their happy times - we are all better off.